Ultrasonic surgical instrument with piezoelectric central lumen transducer

ABSTRACT

A surgical instrument includes a transducer assembly with a housing having a conduit section and a base portion. A fluid passageway is defined through the conduit and base portion, an ultrasonic transducer including a plurality of piezoelectric elements and a plurality of electrodes are arranged in a stack configuration, where an electrode is located between each pair of piezoelectric elements. A first borehole is defined through the ultrasonic transducer and an end mass having a second borehole defined therethrough. A surface of the end mass is positioned adjacent a first end of the ultrasonic transducer, the end mass is configured to engage with the housing, and the conduit section of the housing is configured to pass through the second borehole of the end mass. The end mass is configured to compress the ultrasonic transducer against a surface of the housing when the end mass is engaged with the housing.

PRIORITY

This application is a continuation application claiming priority under35 U.S.C. § 120 to U.S. patent application Ser. No. 15/626,768, entitledULTRASONIC SURGICAL INSTRUMENT WITH PIEZOELECTRIC CENTRAL LUMENTRANSDUCER, filed Jun. 19, 2017, now U.S. Patent Application PublicationNo. 2018/0014846, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/381,785, entitled ULTRASONIC SURGICAL INSTRUMENTWITH PIEZOELECTRIC CENTRAL LUMEN TRANSDUCER, and filed on Aug. 31, 2016,and U.S. Provisional Patent Application Ser. No. 62/361,136, entitledULTRASONIC SURGICAL INSTRUMENT WITH PIEZOELECTRIC TRANSDUCER, and filedon Jul. 12, 2016, each of which is herein entirely incorporated byreference.

TECHNICAL FIELD

The present disclosure generally relates to ultrasonic surgical systemsand, more particularly, to ultrasonic systems that allows surgeons toperform cutting and coagulation and adapt and customize techniques forperforming such procedures.

BACKGROUND

Ultrasonic surgical instruments are finding increasingly widespreadapplications in surgical procedures by virtue of the unique performancecharacteristics of such instruments. Depending upon specific instrumentconfigurations and operational parameters, ultrasonic surgicalinstruments can provide substantially simultaneous cutting of tissue andhemostasis by coagulation, desirably minimizing patient trauma. Thecutting action is typically realized by an-end effector, or blade tip,at the distal end of the instrument, which transmits ultrasonic energyto tissue brought into contact with the end effector. Ultrasonicinstruments of this nature can be configured for open surgical use,laparoscopic, or endoscopic surgical procedures includingrobotic-assisted procedures.

Some surgical instruments utilize ultrasonic energy for both precisecutting and controlled coagulation. Ultrasonic energy cuts andcoagulates by vibrating a blade in contact with tissue. Vibrating athigh frequencies (e.g., 55,500 times per second), the ultrasonic bladedenatures protein in the tissue to form a sticky coagulum. Pressureexerted on tissue with the blade surface collapses blood vessels andallows the coagulum to form a hemostatic seal. The precision of cuttingand coagulation is controlled by the surgeon's technique and adjustingthe power level, blade edge, tissue traction, and blade pressure.

Some areas of improvement for ultrasonic surgical instruments exist. Thecost of such instruments remains a barrier for wider applicability. Forexample, the cost of the transducer has to be lowered substantially toallow for the integration of a transducer into a single patient usedevice. One of the cost drivers for transducers is the complexity of thepiezoelectric element(s) or combination of elements being used. It wouldbe desirable to provide a surgical instrument that overcomes some of thedeficiencies of current instruments. The surgical system describedherein overcomes those deficiencies.

SUMMARY

According to aspects of the present disclosure, a cost-effectivegeometry for a piezoelectric transducer production is a round plate ordisk. The usage of paired parallel plates in combination with wetassembly, the geometric tolerances of the individual plate surfaces andparallelism may also be used to improve the performance of and lower thecost of ultrasonic surgical instruments. Additionally, aspects of thepresent disclosure include a combination of an externally compressedpiezoelectric stack and a central fluid lumen that combine to form apackage enabling an ultrasonic surgical instrument to be used inprocedures that require introduction or removal of fluid.

Aspects of the present disclosure also provide improved efficiencyrelative to a distal flange style half wave transducer because apiezoelectric transducer may be located at the node. Additionally oralternatively, aspects of the present disclosure may provide improvedefficiency based on providing a compact form factor (in one aspect,there is a savings of approximately 0.250″ on an outer diameter of atransducer assembly), comparative cost savings through elimination ofcomponents (e.g. a housing and end cap), robust sealing due to reductionin leak paths, and elimination or reduction of elastomeric componentsused for sealing. Welded and sealed transducers could be exposeddirectly to the body, tissues, blood, etc. with a minimal risk ofexposure to the moisture-sensitive electrode elements and metallizationof the ceramic disks. Accordingly, these aspects may improve longevityof a transducer, which would enable more procedures. An increase in thenumber of procedures performed can reduce the cost of goods sold furthersince the costs would be amortized over more procedures.

Aspects of the present disclosure provide a central lumen that can beimplemented axisymmetrically about the centerline of an ultrasonictransducer in a transducer assembly for use in an ultrasonic surgicalinstrument. In many instances, it is desirable to deliver fluid to orremove fluid from the tissue effecting region of an ultrasonic basedenergy device. A central lumen may act as a conduit for fluid transport.In order to create a spatially economic package, the component reactingto the compression force of the piezoelectric elements of the ultrasonictransducer may be located radially external to the disks. According toaspects, the architecture of a piezoelectric transducer disclosed hereinsimplifies the implementation of the central lumen. Additionally,external threads (or other fastening mechanism) on the componentdefining the lumen allow for the constant distribution of materialspanning the entire length of the lumen within the transducer. Thisconstant distribution may also negate the need for sealing (based on anO-ring, a interference or press fit, etc.), which may encumber cleaning,sanitizing, or sterilization processes for a surgical instrument.Benefits of the present disclosure may include reduction in the size ofradial packages, especially when compared to a centrally locatedcompression mechanism, (e.g. a bolt). Benefits may also include cooleroperating temperatures that allow for higher available tissue power,elimination of the necessity of lumen sealing within an ultrasonictransducer region, facilitation of simple electrical connections, andalignment of electrodes for construction of the transducer assembly.

In one aspect, an apparatus is provided for dissecting and coagulatingtissue. The apparatus comprises: a surgical instrument having an endeffector configured to interact with a tissue at a distal end thereof, agenerator electrically coupled to the surgical instrument and configuredto deliver ultrasonic energy to the end effector to allow the endeffector to interact with the tissue. The surgical instrument comprisesa transducer assembly comprising a housing and an ultrasonic transducer,where the ultrasonic transducer comprises a plurality of piezoelectricelements and a plurality of electrodes arranged in a stack configurationEach of the plurality of electrodes is located between each pair ofsolid piezoelectric elements, with an end mass positioned adjacent afirst end of the ultrasonic transducer. The end mass is configured toengage with the housing and the end mass is configured to compress theultrasonic transducer against an interior surface of the housing whenthe end mass is engaged with the housing.

In another aspect, the surgical instrument comprises a transducerassembly comprising a housing; an ultrasonic transducer comprising aplurality of solid piezoelectric elements and a plurality of electrodesarranged in a stack configuration having a longitudinal axis, a firstend, and a second end, wherein each of a plurality of electrodes islocated between each pair of solid piezoelectric elements such that anelectrode is located at the first end of the stack configuration, and anelectrode is located at the second end of the stack configuration; anend mass positioned along the longitudinal axis adjacent a first end ofthe ultrasonic transducer and coupled to the ultrasonic transducer,where the end mass is configured to engage with the housing, where theend mass is configured to compress the ultrasonic transducer against aninterior surface of the housing when the end mass is engaged with thehousing, and where a first solid piezoelectric element of the pluralityof solid piezoelectric elements and a second solid piezoelectric elementof the plurality of solid piezoelectric elements are electricallyconnected in parallel.

In another aspect, a surgical instrument comprises a transducer assemblycomprising a housing, an ultrasonic transducer, and an end mass having afirst end, a second end, and an aperture therethrough. The ultrasonictransducer comprises a plurality of piezoelectric elements and aplurality of electrodes arranged in a stack configuration having a firstend and a second end, wherein a first electrode is located between afirst pair of piezoelectric elements, a second electrode is locatedbetween a second pair of piezoelectric elements, a third electrode islocated at the first end of the stack configuration, and a fourthelectrode is located at the second end of the stack configuration, afirst spacer element positioned in contact with the third electrode, anda second spacer element positioned in contact with the fourth electrode.The end mass is positioned adjacent a first end of the ultrasonictransducer, wherein the end mass is configured to engage with thehousing and the end mass is configured to compress the ultrasonictransducer against an interior surface of the housing when the end massis engaged with the housing. In addition, the first end of the end masscontacts the first spacer element when the end mass compresses theultrasonic transducer and the second spacer element contacts theinterior surface of the housing when the end mass compresses theultrasonic transducer.

In another aspect, a surgical instrument for coagulating and dissectingtissue comprises a transducer assembly that comprises a housing, anultrasonic transducer, and an end mass. The housing comprises a conduitsection and a base portion, where a fluid passageway is defined throughthe conduit section and the base portion. The ultrasonic transducercomprises a plurality of piezoelectric elements and a plurality ofelectrodes arranged in a stack configuration, where each of theplurality of electrodes is located between each pair of piezoelectricelements and a first borehole is defined through the ultrasonictransducer. The end mass comprises a second borehole definedtherethrough, a surface of the end mass is positioned adjacent a firstend of the ultrasonic transducer, and the end mass is configured toengage with the housing. Further, the conduit section of the housing isconfigured to pass through the first borehole of the ultrasonictransducer and the second borehole of the end mass and the end mass isconfigured to compress the ultrasonic transducer against an interiorsurface of the housing when the end mass is engaged with the housing.

In another aspect, a surgical instrument for coagulating and dissectingtissue comprises a transducer assembly that comprises a housing, anultrasonic transducer, and an end mass. The housing comprises a conduitsection and a base portion, where a fluid passageway is defined throughthe conduit section and the base portion. The ultrasonic transducercomprises a plurality of piezoelectric elements and a plurality ofelectrodes arranged in a stack configuration, and the ultrasonictransducer has a longitudinal axis, a first end, and a second end. Afirst borehole is defined through the ultrasonic transducer, where eachof the plurality of electrodes is located between each pair ofpiezoelectric elements, a second electrode is located at the first endof the ultrasonic transducer, and a third electrode is located at thesecond end of the ultrasonic transducer. The end mass comprises a secondborehole defined therethrough and the end mass positioned along thelongitudinal axis and adjacent a first end of the ultrasonic transducer,where the end mass is configured to engage with the housing. The conduitsection of the housing is configured to pass through the first boreholeof the ultrasonic transducer and the second borehole of the end mass,and the end mass is configured to compress the ultrasonic transduceragainst a surface of the housing when the end mass is engaged with thehousing, and a first piezoelectric element of the plurality ofpiezoelectric elements and a second piezoelectric element of theplurality of piezoelectric elements are electrically connected inparallel.

In another aspect, a transducer assembly comprises a housing, aconductive element, an insulator, and an ultrasonic transducer. Thehousing comprises a conduit section and a base portion, where a fluidpassageway is defined through the conduit section and the base portion.The conductive element at least partially surrounds the conduit sectionof the housing and the insulator is positioned between the conductiveelement and the conduit section so that the insulator electricallyisolates the conductive element from the conduit section. The ultrasonictransducer comprises a plurality of piezoelectric elements and aplurality of electrodes arranged in a stack configuration. Theultrasonic transducer has a longitudinal axis, a first end, and a secondend, where a first borehole is defined through the ultrasonictransducer, each of the plurality of electrodes is located between eachpair of piezoelectric elements, a second electrode is located at thefirst end of the ultrasonic transducer, and a third electrode is locatedat the second end of the ultrasonic transducer. Further, each of theplurality of electrodes is electrically coupled to the conductiveelement. The end mass comprises a second borehole defined therethroughand the end mass is positioned along the longitudinal axis and adjacenta first end of the ultrasonic transducer. The end mass is configured toengage with the housing, the conduit section of the housing isconfigured to pass through the first borehole of the ultrasonictransducer and the second borehole of the end mass, the end mass isconfigured to compress the ultrasonic transducer against a surface ofthe housing when the end mass is engaged with the housing, and a firstpiezoelectric element of the plurality of piezoelectric elements and asecond piezoelectric element of the plurality of piezoelectric elementsare electrically connected in parallel.

In addition to the foregoing, various other method and/or system and/orprogram product aspects are set forth and described in the teachingssuch as text (e.g., claims and/or detailed description) and/or drawingsof the present disclosure.

The foregoing is a summary and thus may contain simplifications,generalizations, inclusions, and/or omissions of detail; consequently,those skilled in the art will appreciate that the summary isillustrative only and is NOT intended to be in any way limiting. Otheraspects, features, and advantages of the devices and/or processes and/orother subject matter described herein will become apparent in theteachings set forth herein.

In one or more various aspects, related systems include but are notlimited to circuitry and/or programming for effecting herein-referencedmethod aspects; the circuitry and/or programming can be virtually anycombination of hardware, software, and/or firmware configured to affectthe herein-referenced method aspects depending upon the design choicesof the system designer. In addition to the foregoing, various othermethod and/or system aspects are set forth and described in theteachings such as text (e.g., claims and/or detailed description) and/ordrawings of the present disclosure.

Further, it is understood that any one or more of thefollowing-described aspects, expressions of aspects, examples, can becombined with any one or more of the other following-described aspects,expressions of aspects, and examples.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, forms, andfeatures described above, further aspects, forms, and features willbecome apparent by reference to the drawings and the following detaileddescription.

FIGURES

The novel features of the described aspects are set forth withparticularity in the appended claims. The described aspects, however,both as to organization and methods of operation, may be best understoodby reference to the following description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a diagram of one aspect of a surgical system comprising agenerator and various surgical instruments usable therewith;

FIG. 2 is a diagram of various aspects of the surgical system shown inFIG. 1;

FIG. 3 is a diagram of one aspect of the combination ultrasonic andelectrosurgical instrument of FIGS. 1 and 2;

FIG. 4 is a model of one aspect of an equivalent circuit of anultrasonic transducer illustrating a motional branch current;

FIG. 5 is a partial sectional view of one aspect of an ultrasonictransducer assembly;

FIG. 6 is a perspective view of an ultrasonic transducer component ofthe ultrasonic transducer assembly shown in FIG. 5;

FIG. 7 is a partial sectional view of the transducer assembly shown inFIG. 5 showing an opening defined by a housing portion of the transducerassembly;

FIG. 8 is a finite element analysis mesh of the stresses on thetransducer assembly shown in FIG. 5;

FIG. 9 is a front view of an aspect of a combination end mass andultrasonic transducer of the present disclosure;

FIG. 10 is a top view of an aspect of a first electrode of the presentdisclosure;

FIG. 11 is a top view of an aspect of a second electrode of the presentdisclosure;

FIG. 12 is a top view of an aspect of a third electrode of the presentdisclosure;

FIG. 13 is a cross sectional view of another aspect of a transducerassembly of the present disclosure;

FIG. 14 is a cross sectional view of an aspect of a transducer assemblyof the present disclosure;

FIG. 15 is a top view of the transducer assembly shown in FIG. 14;

FIG. 16 is an exploded view of an aspect of a transducer assembly of thepresent disclosure;

FIG. 17 is a photograph of a transducer assembly of the presentdisclosure;

FIG. 18 is a photograph of the transducer assembly shown in FIG. 17;

FIG. 19 is a front view of another transducer assembly of the presentdisclosure;

FIG. 20 is a perspective view of another transducer assembly of thepresent disclosure;

FIG. 21 is a perspective view of a piston device of the presentdisclosure;

FIG. 22 is a perspective view of a socket head device of the presentdisclosure;

FIG. 23 is a diagram of one aspect of a surgical system including anultrasonic surgical instrument;

FIG. 24 is a cross section of an aspect of an ultrasonic surgicalinstrument;

FIG. 25 is a perspective view of one aspect of an ultrasonic transducerassembly;

FIG. 26 is a cross section of the ultrasonic transducer assembly shownin FIG. 25;

FIG. 27 is a perspective view of an aspect of a housing of theultrasonic transducer assembly shown in FIG. 25;

FIG. 28 is a perspective view of components of an aspect of anultrasonic transducer assembly shown in FIG. 25;

FIG. 29 is another perspective view of components of an aspect of theultrasonic transducer assembly shown in FIG. 25;

FIG. 30 is a perspective view of an aspect of an electrode of theultrasonic transducer assembly shown in FIG. 25;

FIG. 31 is a perspective view of an aspect of an electrode of theultrasonic transducer assembly shown in FIG. 25;

FIG. 32 is a close up view of an aspect of an electrode and conductiveelement of the ultrasonic transducer assembly shown in FIG. 25; and

DESCRIPTION

Before explaining various aspects of surgical instruments in detail, itshould be noted that the illustrative aspects are not limited inapplication or use to the details of construction and arrangement ofparts illustrated in the accompanying drawings and description. Theillustrative aspects may be implemented or incorporated in otheraspects, variations and modifications, and may be practiced or carriedout in various ways. Further, unless otherwise indicated, the terms andexpressions utilized herein have been chosen for the purpose ofdescribing the illustrative aspects for the convenience of the readerand are not for the purpose of limitation thereof.

Further, it is understood that any one or more of thefollowing-described aspects, expressions of aspects, examples, can becombined with any one or more of the other following-described aspects,expressions of aspects, and examples.

Various aspects are directed to improved ultrasonic and/or combinationelectrosurgical (RF) and ultrasonic instruments configured for effectingtissue dissecting, cutting, and/or coagulation during surgicalprocedures. In one aspect, a combined ultrasonic and electrosurgicalinstrument may be configured for use in open surgical procedures, buthas applications in other types of surgery, such as laparoscopic,endoscopic, and robotic-assisted procedures. Versatile use isfacilitated by selective use of ultrasonic and/or ultrasonic and RFenergy.

The various aspects will be described in association with an ultrasonicinstrument as described herein. Such description is provided by way ofexample, and not limitation, and is not intended to limit the scope andapplications thereof. For example, any one of the described aspects isuseful in combination with a multitude of ultrasonic instrumentsincluding those described in, for example, U.S. Pat. Nos. 5,322,055;5,449,370; 5,630,420; 5,935,144; 5,938,633; 5,944,737; 5,954,736;6,278,218; 6,283,981; 6,309,400; 6,325,811; 6,387,109; 6,491,708;7,821,143; 8,147,508; 8,152,825; 8,277,471; 8,430,898; 8,512,364;8,882,792; and 9,114,245; and U.S. Patent Application Publication Nos.US20050192612; US2011/0040212; US2011/0040213; US20120215244;20130090576; 20130197550; and US20130253558, each of which areincorporated by reference herein in its entirety.

As will become apparent from the following description, it iscontemplated that aspects of the surgical instruments described hereinmay be used in association with an oscillator unit of a surgical system,whereby ultrasonic energy from the oscillator unit provides the desiredultrasonic actuation for the present surgical instrument. It is alsocontemplated that aspects of the surgical instrument described hereinmay be used in association with a signal generator unit of a surgicalsystem, whereby electrical energy in the form of radio frequencies (RF),for example, is used to provide feedback to the user regarding thesurgical instrument. The ultrasonic oscillator and/or the signalgenerator unit may be non-detachably integrated with the surgicalinstrument or may be provided as separate components, which can beelectrically attachable to the surgical instrument.

One aspect of the present surgical apparatus is particularly configuredfor disposable use by virtue of its straightforward construction.However, it is also contemplated that other aspects of the presentsurgical instrument can be configured for non-disposable or multipleuses. Detachable connection of the present surgical instrument with anassociated oscillator and signal generator unit is presently disclosedfor single-patient use for illustrative purposes only. However,non-detachable integrated connection of the present surgical instrumentwith an associated oscillator and/or signal generator unit is alsocontemplated. Accordingly, various aspects of the presently describedsurgical instruments may be configured for single use and/or multipleuse with either detachable and/or non-detachable integral oscillatorand/or signal generator unit, without limitation, and all combinationsof such configurations are contemplated to be within the scope of thepresent disclosure.

With reference to FIGS. 1-3, one aspect of a surgical system 100including an ultrasonic surgical instrument is described. FIGS. 1 and 2illustrate one aspect of a surgical system 100 comprising a generator102 and various surgical instruments 104, 108 usable with the surgicalsystem 100. FIG. 3 is a diagram of the ultrasonic surgical instrument104 of FIGS. 1 and 2.

In various aspects, the generator 102 may comprise several separatefunctional elements, such as modules and/or blocks. Different functionalelements or modules may be configured for driving the different kinds ofsurgical instruments 104, 108. For example, an ultrasonic generatordrive circuit 114 may drive ultrasonic devices such as the ultrasonicsurgical instrument 104 via a cable 142. An electrosurgery/RF generatordrive circuit 116 may drive the electrosurgical instrument (not shown)via a cable (not shown). For example, the respective drive circuits 114,116 may generate respective drive signals for driving an appropriatesurgical instrument 104, 108. In various aspects, the ultrasonicgenerator drive circuit 114 (e.g., ultrasonic drive circuit) and/or theelectrosurgery/RF generator drive circuit 116 (e.g., RF drive circuit)each may be formed integrally with the generator 102. Alternatively, oneor more of the drive circuits 114, 116 may be provided as a separatecircuit module electrically coupled to the generator 102. (The drivecircuits 114 and 116 are shown in phantom to illustrate this option.)Also, in some aspects, the electrosurgery/RF generator drive circuit 116may be formed integrally with the ultrasonic generator drive circuit114, or vice versa. Also, in some aspects, the generator 102 may beomitted entirely and the drive circuits 114, 116 may be executed byprocessors or other hardware within the respective surgical instruments104, 108.

In other aspects, the electrical outputs of the ultrasonic generatordrive circuit 114 and the electrosurgery/RF generator drive circuit 116may be combined into a single drive circuit to provide a singleelectrical signal capable of driving the multifunction surgicalinstrument 108 simultaneously with electrosurgical RF and ultrasonicenergies via a cable 146. The multifunction surgical instrument 108comprises an ultrasonic transducer component 120 coupled to anultrasonic blade 149 and one or more electrodes in the end effector 124to receive electrosurgical RF energy. In such implementations, thecombined RF/ultrasonic signal is coupled to the multifunction surgicalinstrument 108. The multifunction surgical instrument 108 comprisessignal processing components to split the combined RF/ultrasonic signalsuch that the RF signal can be delivered to the electrodes in the endeffector 125 and the ultrasonic signal can be delivered to theultrasonic transducer component 120.

In accordance with the described aspects, the ultrasonic generator drivecircuit 114 may produce a drive signal or signals of particularvoltages, currents, and frequencies, e.g., 55,500 cycles per second(Hz). The drive signal or signals may be provided to the ultrasonicsurgical instrument 104, and specifically to the transducer component120, which may operate, for example, as described herein. The transducercomponent 120 and a waveguide extending through the shaft 126 (waveguidenot shown in FIG. 1) may collectively form an ultrasonic drive systemdriving an ultrasonic blade 128 of an end effector 122. In one aspect,the generator 102 may be configured to produce a drive signal of aparticular voltage, current, and/or frequency output signal that can bemodified with high resolution, accuracy, and repeatability.

The generator 102 may be activated to provide the drive signal to thetransducer component 120 in any suitable manner. For example, thegenerator 102 may comprise a foot switch 130 coupled to the generator102 via a foot switch cable 132. A clinician may activate the transducercomponent 120 by depressing the foot switch 130. In addition, or insteadof the foot switch 130 some aspects of the ultrasonic surgicalinstrument 104 may utilize one or more switches positioned on the handpiece that, when activated, may cause the generator 102 to activate thetransducer component 120. In one aspect, for example, the one or moreswitches may comprise a pair of toggle buttons 134 a, 134 b (FIG. 2),for example, to determine an operating mode of the surgical instrument104. When the toggle button 134 a is depressed, for example, theultrasonic generator 102 may provide a maximum drive signal to thetransducer component 120, causing it to produce maximum ultrasonicenergy output. Depressing toggle button 134 b may cause the ultrasonicgenerator 102 to provide a user-selectable drive signal to thetransducer component 120, causing it to produce less than the maximumultrasonic energy output. The surgical instrument 104 additionally oralternatively may comprise a second switch (not shown) to, for example,indicate a position of a jaw closure trigger for operating jaws of theend effector 122. Also, in some aspects, the ultrasonic generator 102may be activated based on the position of the jaw closure trigger,(e.g., as the clinician depresses the jaw closure trigger to close thejaws, ultrasonic energy may be applied). Additionally or alternatively,the one or more switches may comprise a toggle button 134 c that, whendepressed, causes the generator 102 to provide a pulsed output. Thepulses may be provided at any suitable frequency and grouping, forexample. In certain aspects, the power levels of the pulses may be thesame as the power levels associated with toggle buttons 134 a, 134 b(maximum, less than maximum), for example.

In accordance with the described aspects, the electrosurgery/RFgenerator drive circuit 116 may generate a drive signal or signals withoutput power sufficient to perform bipolar electrosurgery using radiofrequency (RF) energy. In bipolar electrosurgery applications, the drivesignal may be provided, for example, to electrodes of an electrosurgicalinstrument (not shown), for example. Accordingly, the generator 102 maybe configured for therapeutic purposes by applying electrical energy tothe tissue sufficient for treating the tissue (e.g., coagulation,cauterization, tissue welding).

The generator 102 may comprise an input device 110 located, for example,on a front panel of the generator 102 console. The input device 110 maycomprise any suitable device that generates signals suitable forprogramming the operation of the generator 102. In operation, the usercan program or otherwise control operation of the generator 102 usingthe input device 110. The input device 110 may comprise any suitabledevice that generates signals that can be used by the generator (e.g.,by one or more processors contained in the generator) to control theoperation of the generator 102 (e.g., operation of the ultrasonicgenerator drive circuit 114 and/or electrosurgery/RF generator drivecircuit 116). In various aspects, the input device 110 includes one ormore of buttons, switches, thumbwheels, keyboard, keypad, touch screenmonitor, pointing device, remote connection to a general purpose ordedicated computer. In other aspects, the input device 110 may comprisea suitable user interface, such as one or more user interface screensdisplayed on a touch screen monitor, for example. Accordingly, by way ofthe input device 110, the user can set or program various operatingparameters of the generator, such as, for example, current (I), voltage(V), frequency (f), and/or period (T) of a drive signal or signalsgenerated by the ultrasonic generator drive circuit 114 and/orelectrosurgery/RF generator drive circuit 116.

The generator 102 also may comprise an output device 112 (FIGS. 1, 2),such as an output indicator, located, for example, on a front panel ofthe generator 102 console. The output device 112 includes one or moredevices for providing a sensory feedback to a user. Such devices maycomprise, for example, visual feedback devices (e.g., a visual feedbackdevice may comprise incandescent lamps, light emitting diodes (LEDs),graphical user interfaces (GUIs), displays, analog indicators, digitalindicators, bar graph displays, digital alphanumeric displays, lightcrystal display (LCD) display screens, LED indicators), audio feedbackdevices (e.g., an audio feedback device may comprise speakers, buzzers,audible devices, computer generated tones, computerized speechs, voiceuser interfaces (VUIs) to interact with computers through a voice/speechplatform), or tactile feedback devices (e.g., a tactile feedback devicecomprises any type of vibratory feedback, haptic actuator).

In one aspect, the ultrasonic generator drive circuit 114 andelectrosurgery/RF drive circuit 116 may comprise one or more embeddedapplications implemented as firmware, software, hardware, or anycombination thereof. The drive circuits 114, 116 may comprise variousexecutable modules such as software, programs, data, drivers,application program interfaces (APIs), and so forth. The firmware may bestored in nonvolatile memory (NVM), such as in bit-masked read-onlymemory (ROM) or flash memory. In various implementations, storing thefirmware in ROM may preserve flash memory. The NVM may comprise othertypes of memory including, for example, programmable ROM (PROM),erasable programmable ROM (EPROM), electrically erasable programmableROM (EEPROM), or battery backed random-access memory (RAM) such asdynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronousDRAM (SDRAM).

In one aspect, the drive circuits 114, 116 comprise a hardware componentimplemented as a processor for executing program instructions formonitoring various measurable characteristics of the surgicalinstruments 104, 108 and generating a corresponding output controlsignals for operating the surgical instruments 104, 108. In aspects inwhich the generator 102 is used in conjunction with the surgicalinstrument 104, the output control signal may drive the ultrasonictransducer component 120 in cutting and/or coagulation operating modes.Electrical characteristics of the surgical instrument 104 and/or tissuemay be measured and used to control operational aspects of the generator102 and/or provided as feedback to the user. In aspects in which thegenerator 102 is used in conjunction with an electrosurgical instrument,the output control signal may supply electrical energy (e.g., RF energy)to the end effector of the electrosurgical instrument in cutting,coagulation and/or desiccation modes. Electrical characteristics of theelectrosurgical instrument and/or tissue may be measured and used tocontrol operational aspects of the generator 102 and/or provide feedbackto the user. In various aspects, as previously discussed, the hardwarecomponent may be implemented as a digital signal processor (DSP),programmable logic device (PLD), application-specific integrated circuit(ASIC), other circuit, and/or register. In one aspect, the processor maybe configured to store and execute computer software programinstructions to generate the output signal functions for driving variouscomponents of the surgical instruments 104, 108, such as the ultrasonictransducer component 120 and the end effectors 122, 125.

Although certain modules, circuits, and/or blocks of the generator 102may be described by way of example, it can be appreciated that a greateror lesser number of modules, circuits, and/or blocks may be used andstill fall within the scope of the aspects. Further, although variousaspects may be described in terms of modules, circuits, and/or blocks tofacilitate description, such modules, circuits, and/or blocks may beimplemented by one or more hardware components, e.g., processors, DSPs,PLDs, ASICs, circuits, registers and/or software components, e.g.,programs, subroutines, logic and/or combinations of hardware andsoftware components. Also, in some aspects, the various modulesdescribed herein may be implemented utilizing similar hardwarepositioned within the surgical instruments 104, 108 (i.e., the generator102 may be omitted).

FIG. 2 illustrates generator 102 configured to drive multiple surgicalinstruments 104, 108. The first surgical instrument 104 comprises ahandpiece 105, an ultrasonic transducer component 120, a shaft 126, andan end effector 122. The end effector 122 comprises an ultrasonic blade128 acoustically coupled to the transducer component 120 and a clamp arm140. The handpiece 105 comprises a trigger 143 to operate the clamp arm140 and a combination of the toggle buttons 134 a, 134 b, 134 c toenergize and drive the ultrasonic blade 128 or other function. Thetoggle buttons 134 a, 134 b, 134 c can be configured to energize theultrasonic transducer component 120 with the generator 102. Still withreference to FIG. 2, the generator 102 also is configured to drive acombination electrosurgical and ultrasonic instrument 108. Thecombination electrosurgical and ultrasonic multifunction surgicalinstrument 108 comprises a handpiece 109, a shaft 129, and an endeffector 125. The end effector comprises an ultrasonic blade 149 and aclamp arm 145. The ultrasonic blade 149 is acoustically coupled to theultrasonic transducer component 120. The handpiece 109 comprises atrigger 147 to operate the clamp arm 145 and a combination of the togglebuttons 137 a, 137 b, 137 c to energize and drive the ultrasonic blade149 or other function. The toggle buttons 137 a, 137 b, 137 c can beconfigured to energize the ultrasonic transducer component 120 with thegenerator 102 and energize the ultrasonic blade 149 with a bipolarenergy source also contained within the generator 102. The generator 102is coupled to an ultrasonic transducer component 120 of the combinationelectrosurgical and ultrasonic instrument 108 via a cable 142.

The generator 102 also is configured to drive a surgical instrument 104.The generator 102 is coupled to an ultrasonic transducer component 120of the surgical instrument 104 via a cable 146 (See FIG. 1). Theultrasonic transducer component 120 of the surgical instrument 104 and awaveguide extending through a shaft 126 (waveguide not shown in FIG. 2)may collectively form an ultrasonic drive system driving an ultrasonicblade 128 of an end effector 122. The end effector 122 further maycomprise a clamp arm 140 to clamp tissue between the clamp arm 140 andthe ultrasonic blade 128. In one aspect, the generator 102 may beconfigured to produce a drive signal of a particular voltage, current,and/or frequency output signal that can be stepped or otherwise modifiedwith high resolution, accuracy, and repeatability.

It will be appreciated that the surgical instrument 104 may comprise anycombination of the toggle buttons 134 a, 134 b, 134 c. For example, thesurgical instrument 104 could be configured to have only two togglebuttons: a toggle button 134 a for producing maximum ultrasonic energyoutput and a toggle button 134 c for producing a pulsed output at eitherthe maximum or less than maximum power level. In this way, the drivesignal output configuration of the generator 102 could be 5 continuoussignals and or a suitable number of (e.g. between 1 to 5) pulsedsignals. In certain aspects, the specific drive signal configuration maybe controlled based upon, for example, EEPROM settings in the generator102 and/or user power level selection(s). In certain aspects, atwo-position switch may be provided as an alternative to a toggle button134 c. For example, a surgical instrument 104 may include a togglebutton 134 a for producing a continuous output at a maximum power leveland a two-position toggle button 134 b. In a first position, togglebutton 134 b may produce a continuous output at a less than maximumpower level, and in a second position the toggle button 134 b mayproduce a pulsed output (e.g., at either a maximum or less than maximumpower level, depending upon the EEPROM settings).

With reference to FIG. 3, aspects of the generator 102 may enablecommunication with instrument-based data circuits. For example, thegenerator 102 may be configured to communicate with a first data circuit136 and/or a second data circuit 138. For example, the first datacircuit 136 may indicate a burn-in frequency slope, as described herein.Additionally or alternatively, any type of information may becommunicated to second data circuit 138 for storage therein via a datacircuit interface (e.g., using a logic device). Such information maycomprise, for example, an updated number of operations in which theinstrument has been used and/or dates and/or times of its usage. Incertain aspects, the second data circuit may transmit data acquired byone or more sensors (e.g., an instrument-based temperature sensor). Incertain aspects, the second data circuit 138 may receive data from thegenerator 102 and provide an indication to a user (e.g., an LEDindication or other visible indication) based on the received data. Thesecond data circuit 138 may be contained in the multifunction surgicalinstrument 108. In some aspects, the second data circuit 138 may beimplemented in a manner similar to that of the first data circuit 136described herein.

An instrument interface circuit may comprise a second data circuit 138interface to enable this communication. In one aspect, the second datacircuit interface may comprise a tri-state digital interface, althoughother interfaces also may be used. In certain aspects, the second datacircuit 138 may generally be any circuit for transmitting and/orreceiving data. In one aspect, for example, the second data circuit 138may store information pertaining to the particular surgical instrumentwith which it is associated. Such information may include, for example,a model number, a serial number, a number of operations in which thesurgical instrument has been used, and/or any other type of information.In some aspects, the second data circuit 138 may store information aboutthe electrical and/or ultrasonic properties of an associated transducercomponent 120, end effector 122, or ultrasonic drive system. Variousprocesses and techniques described herein may be executed by agenerator. It will be appreciated, however, that in certain aspects, allor a part of these processes and techniques may be performed by internallogic 139 of the multifunction surgical instrument 108.

Furthermore, the generator 102 may be configured to functionally operatein a manner similar to the GEN300 sold by Ethicon Endo-Surgery, Inc. ofCincinnati, Ohio as is disclosed in one or more of the following U.S.patents, all of which are incorporated by reference herein: U.S. Pat.No. 6,480,796 (Method for Improving the Start Up of an Ultrasonic SystemUnder Zero Load Conditions); U.S. Pat. No. 6,537,291 (Method forDetecting Blade Breakage Using Rate and/or Impedance Information); U.S.Pat. No. 6,662,127 (Method for Detecting Presence of a Blade in anUltrasonic System); U.S. Pat. No. 6,678,899 (Method for DetectingTransverse Vibrations in an Ultrasonic Surgical System); U.S. Pat. No.6,977,495 (Detection Circuitry for Surgical Handpiece System); U.S. Pat.No. 7,077,853 (Method for Calculating Transducer Capacitance toDetermine Transducer Temperature); U.S. Pat. No. 7,179,271 (Method forDriving an Ultrasonic System to Improve Acquisition of Blade ResonanceFrequency at Startup); and U.S. Pat. No. 7,273,483 (Apparatus and Methodfor Alerting Generator Function in an Ultrasonic Surgical System.

FIG. 4 illustrates an equivalent circuit 150 of an ultrasonictransducer, such as the ultrasonic transducer component 120 shown inFIGS. 1-3, according to one aspect. The circuit 150 comprises a first“motional” branch having a serially connected inductance L_(s),resistance R_(s) and capacitance C_(s) that define the electromechanicalproperties of the resonator, and a second capacitive branch having astatic capacitance C_(o). Drive current I_(g) may be received from agenerator at a drive voltage V_(g), with motional current I_(m) flowingthrough the first branch and current I_(g)-I_(m) flowing through thecapacitive branch. Control of the electromechanical properties of theultrasonic transducer may be achieved by suitably controlling I_(g) andV_(g). As explained above, conventional generator architectures mayinclude a tuning inductor L_(t) (shown in phantom in FIG. 4) for tuningout in a parallel resonance circuit the static capacitance Co at aresonant frequency so that substantially all of generator's currentoutput I_(g) flows through the motional branch. In this way, control ofthe motional branch current I_(m) is achieved by controlling thegenerator current output I_(g). The tuning inductor L_(t) is specific tothe static capacitance C_(o) of an ultrasonic transducer, however, and adifferent ultrasonic transducer having a different static capacitancerequires a different tuning inductor L_(t). Moreover, because the tuninginductor L_(t) is matched to the nominal value of the static capacitanceC_(o) at a particular resonant frequency, accurate control of themotional branch current I_(m) is assured only at that particularfrequency, and as frequency shifts down with transducer temperature,accurate control of the motional branch current is compromised.

Aspects of the generator 102 shown in FIGS. 1-3 may be configured suchthat they do not rely on a tuning inductor L_(t) to monitor the motionalbranch current I_(m). Instead, the generator 102 may use the measuredvalue of the static capacitance C_(o) in between applications of powerfor a specific ultrasonic surgical instrument 104 (along with drivesignal voltage and current feedback data) to determine values of themotional branch current I_(m) on a dynamic and ongoing basis (e.g., inreal-time). Such aspects of the generator 102 are therefore able toprovide virtual tuning to simulate a system that is tuned or resonantwith any value of static capacitance C_(o) at any frequency, and notjust at the resonant frequency dictated by a nominal value of the staticcapacitance C_(o).

It is noted, for the purpose of describing the various aspects of thepresent disclosure, that an ultrasound transducer assembly is atransducer assembly which ultrasonically vibrates anultrasonically-vibratable medical-treatment instrument (such as, withoutlimitation, an ultrasonic scalpel or an ultrasonic clamp), when attachedto the transducer assembly, in a mode of vibration at a fundamentalfrequency (i.e., a fundamental resonant frequency), that a node is anode of vibration (i.e., a location of zero magnitude of vibration), andthat an antinode is a location of maximum magnitude of vibration.Examples of modes of vibration include, without limitation, alongitudinal mode of vibration, a torsional mode of vibration, a bendingmode of vibration, and a swelling mode of vibration, wherein thetransducer assembly is not limited to operating in a single mode ofvibration as is known to those skilled in the art. Also, the terminology“gain stage” means a positive gain stage and is alongitudinally-extending portion of the transducer assembly whichresults in increased magnitude of vibration. Gain stages may be providedby a portion of the transducer assembly having at least one of a reduceddiameter (as identified in some of the figures), a (constant ornon-constant) taper, or being of a different material, as is known tothose skilled in the art. It is pointed out that piezoelectrictransducer disks are not limited to those with an outer perimeter havinga circular shape and may include those with an outer perimeter havinganother shape such as, without limitation, an elliptical shape.

In one aspect, the present disclosure describes a surgical instrumentthat includes a transducer assembly comprising a housing, an ultrasonictransducer comprising a plurality of piezoelectric elements in a stackconfiguration, and an end mass where the end mass is configured toengage the housing and hold the ultrasonic transducer in a particularrelationship within the housing. According to aspects, the end masscompresses the ultrasonic transducer within a horn shaped portion of thehousing. A first surface of the end mass contacts a first surface of theultrasonic transducer and when the end mass engages with the housing, asecond surface of the ultrasonic transducer is compressed against aninterior surface of the horn shaped portion of the housing. Thecompression of the ultrasonic transducer is caused due to the engagementbetween the end mass and the housing. Such compression is independent ofa bolt or screw that might otherwise be passed through the piezoelectricelements and torqued into the housing. The transducer assembly may beacoustically coupled to an ultrasonic blade of an end effector at adistal end of the surgical instrument and the surgical instrument may bean ultrasonic surgical instrument or a combination ultrasonic andelectrosurgical instrument similar to that shown in FIGS. 1-3. Thetransducer assembly, and hence the ultrasonic transducer, is configuredto receive a drive signal from a generator to cause ultrasonic motion ofthe ultrasonic blade. Further, the terms “proximal” and “distal” mayused with reference the proximity or location of components of thetransducer assembly based on where a clinician may grip a surgicalinstrument that comprises the transducer assembly.

FIGS. 5-8 illustrate one aspect of a transducer assembly 200 comprisinga housing 202 and an ultrasonic transducer 204, where the ultrasonictransducer 204 comprises a plurality of piezoelectric elements 208 a,208 b, 208 c, 208 d arranged in a stack configuration, which may bereferred to as a “Langevin stack”, and having a longitudinal axis 211along the centerline of the piezoelectric elements 208 a-208 d, and anend mass 206 positioned along the longitudinal axis 211 adjacent a firstend of the ultrasonic transducer 204. In one aspect, the stack ofpiezoelectric elements 208 a-208 d comprises four solid disks as shownin FIGS. 5-7 made of a lead zirconate titanate (PZT) material containedin a compression housing. In other aspects, the ultrasonic transducer204 piezoelectric stack may comprise an even multiple (n×2) ofpiezoelectric elements 208 a-208 d. The piezoelectric stack may beassembled wet (glue bonded) directly onto the threaded end mass 206 andequipped with electrically conducive elements such as wires or cables,for example, to connect the piezoelectric stack to an active energysource and ground at the generator 102 (FIGS. 1-3). Accordingly, the endmass 206 and ultrasonic transducer 204 may be separate components thatare then bonded together to allow for assembly of the transducerassembly 200.

The piezoelectric elements 208 a-208 d are electrically connected inparallel and are paired in opposite directions. A first electrode 209 bis disposed between adjacent piezoelectric elements 208 a-208 b, asecond electrode 209 c is disposed between adjacent piezoelectricelements 208 b-208 c, and a third electrode 209 d is disposed betweenadjacent piezoelectric elements 208 c-208 d. A fourth electrode 209 a isdisposed and at the proximal end of the piezoelectric element 208 a anda fifth electrode 209 e is disposed at the end of the piezoelectricelement 208 d. In one configuration, the electrodes 209 a-209 e areformed of an electrically conductive material in thin diskconfiguration. The electrodes 209 a-209 e are configured to electricallycouple to the generator 102 (shown in FIGS. 1-3) to energize thepiezoelectric elements 208 a-208 d. In one configuration, the electrodes209 a, 209 c, 209 e are configured to electrically couple to thenegative polarity or return (−) of the generator 102 output port and theelectrodes 209 b, 209 d are configured to couple to the positivepolarity (+) of the generator 102 output port. In operation, thegenerator 102 applies an alternating voltage potential to the electrodes209 a-209 e to energize the piezoelectric elements 208 a-208 d and causethem to mechanically expand and contract in the longitudinal directionin response to the alternating voltage potential. When the alternatingvoltage potential is in a frequency range of approximately 30-100 kHzthe alternating voltage potential causes the piezoelectric elements 208a-208 d to vibrate at ultrasonic frequencies. One suitable frequencyvalue of the alternating voltage potential may be 55.5 kHz, for example.

Furthermore, the ultrasonic transducer 204 comprises compressionelements 210 located at the ends of the piezoelectric elements 208 a and208 d. In accordance with the present disclosure, the compressionelements 210 provide the points of contact between the end mass 206 andthe ultrasonic transducer 204 at the first end of the transducer 204 andbetween the housing 202 and the ultrasonic transducer 204 at a secondend of the ultrasonic transducer 204. The compression element 210 maycomprise a metal compression plate or spacer that has a size and formfactor that corresponds to the piezoelectric elements 208 a-208 d. Thecompression element 210 may help to avoid damage to the stack ofpiezoelectric elements 208 a-d as the end mass 206 is threaded into andengaged with the housing 202. Compression may prevent the individualpiezoelectric elements 208 a-208 d from being subjected to tension,which may cause mechanical failure. The compression elements 210 mayeach be manufactured from a type of material that is appropriate forapplication in the ultrasonic transducer 204, including metals forexample, such as aluminum, stainless steel, titanium, and/or alloysthereof, or other materials, such as carbon fiber, fiberglass, plastics,etc.

As shown in the example illustrated in FIGS. 5-7, the housing 202comprises a horn shaped portion 220. The horn shaped portion 220 definesan open proximal end for receiving the ultrasonic transducer 204 and awall that surrounds and houses the ultrasonic transducer 204 when it isinserted into an opening 213 defined by the horn shaped portion 220 ofthe housing 202. The horn shaped portion 220 may include internalthreads on the inner wall surface allowing for the end mass 206 to betorqued into place. The horn shaped portion 220 also serves the functionof amplifying the displacement of the ultrasonic transducer 204, and thehorn shaped portion 220 compresses the piezoelectric elements 208 a-208d of the ultrasonic transducer 204. According to various aspects, thediameter of the ultrasonic transducer 204 may be smaller that the innerdiameter of the horn shaped portion 220 of the housing 202. Accordingly,a gap 205 is defined between the ultrasonic transducer 204 and theinterior of the horn shaped portion 220 of the housing 202. This gap 205allows for insertion of the ultrasonic transducer 204 and prevents thepiezoelectric elements 208 a-208 d from coming into unwanted contactwith a side wall of the interior surface of the horn shaped portion 220of the housing 202.

The housing 202 also comprises a flange 216. The flange 216 is shown asan annular ring around the perimeter of the horn shaped portion 220.However, in some aspects, the flange 216 may instead be positioned insections located about the perimeter instead of being arranged as acontinuous ring. In other aspects, there may be additional flangessimilar to and in addition to the flange 216 located at predeterminedlocations on the housing 202. Further, the flange 216 may be located atother locations along the housing 202, for example, the flange 216 maybe located along the housing 202 closer to a distal end of the housing202. According to various aspects, the flange 216 may include an O-ringor other elastomeric material member (not shown) that may providesealing as well as damping of vibrations within the flange 216 and thehousing 202 overall. An O-ring may be mounted within a groove or otherfeature (not shown) of the flange 216. Also, according to variousaspects, the flange 216 may be replaced with a mass having radialdimensions similar to those of the stack 204 and the mass 206. A handpiece housing, or other frame member, of a surgical instrument mayinclude corresponding shapes for receiving the flange 216.

The horn shaped portion 220 of the housing 202 allows for easy assemblyof the transducer assembly 200 and provides advantages in heatdissipation and potential sealing of the ultrasonic transducer 204 andthe stack of piezoelectric elements 208 a-208 d. In another aspect, thehorn shaped portion 220 may be threaded on an outside surface thatmatches the threads on the end mass 206. Thus, the end mass 206 may befit over the horn shaped portion 220 while compressing the ultrasonictransducer 204 when within the horn shaped portion 220 of the housing202. In addition, the housing 202 may comprise a channel 222 forattaching a waveguide section or other instrument section 214. Thechannel 222 may be threaded or may include a quick connect and/or alocking feature for attachment of other components thereto. In variousaspects, the housing 202 and the end mass 206 each may be made as aunitary piece or in sections. Further, the housing 202 and the end mass206 each may be made from a type of metal that is appropriate for theapplication of the transducer assembly, for example, such as aluminum,stainless steel, titanium, and/or alloys thereof. In other aspects, thehousing 202 may be made from other materials, such as carbon fiber,fiberglass, plastic, etc. as appropriate.

The end mass 206 may be coupled to the ultrasonic transducer 204 and theend mass 206 may be fixedly or removably attached with the housing 202.In one aspect, the ultrasonic transducer 204 is coupled to the end mass206 via a suitable bonding mechanism. The ultrasonic transducer 204 andthe end mass 206 may be bonded together via an adhesive, a weld, orother suitable bonding mechanism. In the aspect shown in FIGS. 5-7, theend mass 206 is configured to compress the plurality of piezoelectricelements 208 a-208 d when the end mass 206 is engaged with the housing202. The end mass 206 is configured to engage with the housing 202 via athreaded connection. When the end mass 206 is engaged with the housing202, a second end of the ultrasonic transducer 204 is compressed againstan interior surface of the housing 202. The end mass 206 also comprisesone or more longitudinal channels 218 to allow for wiring to beconnected to the ultrasonic transducer 204. In addition, the end mass206 may comprise a torqueing feature 207 that allows torque to beapplied to the end mass 206. In FIGS. 5-7, the torqueing feature 207 isa hex head. In other aspects, the torqueing feature 207 may be any typeof drive that allows for torqueing the end mass 206; for example, thetorqueing feature 207 may be any type of screw drive.

The piezoelectric elements 208 a-208 d may be fabricated from anysuitable material, such as, for example, lead zirconate-titanate (PZT),lead meta-niobate, lead titanate, barium titanate or other piezoelectricceramic material. As shown in FIGS. 5-7, each of the piezoelectricelements 208 a-d have a circular or disk shaped configuration and areformed as a solid element with an uninterrupted surface. In otheraspects, the piezoelectric elements 208 a-208 d may have differentshapes and/or different surface characteristics, such as apertures forbolting a plurality of elements together. The elements 208 a-208 d mayhave an appropriate aspect factor for a particular application.Additionally, the piezoelectric elements 208 a-208 d may be energizedvia positive electrodes 209 b, 209 d and negative electrodes 209 a, 209c, 209 e respectively positioned between the piezoelectric elements 208a-208 d and at the ends of the piezoelectric elements 208 a and 208 e asshown in FIGS. 5-6. The positive and negative electrodes 209 a-209 e maybe electrically coupled to wires that may be encased within a cable andelectrically connectable to an ultrasonic signal generator 102 of anultrasonic system as described above. The electrodes 209 a-209 e may bethe same as or similar to electrodes 324, 326, and 328 described belowin connection with FIGS. 9 and 10. In addition, according to variousaspects, the piezoelectric elements 208 a-208 d may comprise a boreholethrough each of the elements 208 a-208 d that allows for assembly ofother features of the ultrasonic transducer 204.

Each of positive electrodes 209 b, 209 d, negative electrodes 209 a, 209c, 209 e, and the piezoelectric elements 208 a-208 d that make up theultrasonic transducer 204 each may be a solid element with anuninterrupted surface. Alternatively, the transducer 204 defines a boreextending therethrough. For example, in one aspect, the bore extendsthrough the center of the piezoelectric elements 208 a-208 d. Theultrasonic transducer 204 of the transducer assembly 200 is configuredto convert an electrical signal from an ultrasonic generator, such asgenerator 102 described above in connection with FIGS. 1-3, intomechanical energy that results in primarily a standing acoustic wave oflongitudinal vibratory motion of the ultrasonic transducer 204 and anend effector (not shown in FIGS. 1-8) at ultrasonic frequencies. Inanother aspect, the vibratory motion of the ultrasonic transducer 204may act in a different direction. For example, the vibratory motion maycomprise a local longitudinal component of a more complicated motion ofthe tip of the ultrasonic instrument. When the transducer assembly 200is energized, a vibratory motion standing wave may be generated throughthe transducer assembly 200. The transducer assembly 200 may be designedto operate at a resonance such that an acoustic standing wave pattern ofa predetermined amplitude is produced. The amplitude of the vibratorymotion at any point along the transducer assembly 200 may depend uponthe location along the transducer assembly 200 at which the vibratorymotion is measured. A minimum or zero crossing in the vibratory motionstanding wave is generally referred to as a node (e.g., where motion isusually minimal), and a local absolute value maximum or peak in thestanding wave is generally referred to as an anti-node (e.g., wheremotion is usually maximal). According to aspects, the distance betweenan anti-node and its nearest node may be one-quarter wavelength (λ/4).

Furthermore, the plurality of piezoelectric elements 208 a-208 d andelectrodes 209 a-209 e may be bonded via an adhesive, such as with anepoxy or other glue, a weld, or other suitable bonding mechanism. In oneaspect, surfaces of a piezoelectric element may have an adhesive, suchas epoxy, placed on it and subsequently an electrode 209 a-209 e may beplaced over the adhesive. The adhesive may be provided in a layer suchthat it does not interfere with the electrical connections between theelectrodes 209 a-209 e and the piezoelectric elements 208 a-208 dthemselves. Further, according to aspects, only some of thepiezoelectric elements 208 a-208 d may be bonded together, instead ofthe entire plurality of piezoelectric elements 208 a-208 d. In addition,the plurality of piezoelectric elements 208 a-208 d may be assembleddry, with no adhesive or bonding mechanism between each of the layers.

Additionally, FIG. 8 is a finite element analysis mesh contour plot ofthe stresses at nodes 224 of the transducer assembly 200 that isconfigured as a half wave resonator at 40 kHz, for example. According toaspects, the design of the transducer assembly 200 can be scaled up ordown in frequency and wavelength based on the appropriate application.For example, the transducer assembly 200 may be made to function as aquarter or full wavelength transducer.

FIG. 9 shows a combination of an end mass 306 and ultrasonic transducer304 that may be sized and configured to be located within a housing ofan ultrasonic surgical instrument, such as housing 302 also describedbelow. Any aspects of the end mass 306, ultrasonic transducer 304, andhousing 302, may have the same or similar attributes as end mass 206,ultrasonic transducer 204, and housing 202, respectively, asappropriate. Electrodes 324, 326, and 328, described in more detail inFIGS. 10-12, are shown in adjacent relationship to the piezoelectricelements 308 a-308 d that make up the ultrasonic transducer 304. Asshown in FIG. 9, the end mass 306 has a channel 332 definedtherethrough. The channel 332 may be used for the wiring or cabling thatis connected to one or more of the electrodes 324, 326, and 328 to allowfor energization of the electrodes 324, 326, and 328 and application ofelectricity to the piezoelectric elements 308 a-308 d. The channel 332may further have sealing product, such as solder, epoxy, glue, rubber,or other insulation material, located therein to prevent the entry offoreign substances into the end mass 306 and ultrasonic transducer 304.Furthermore, the channel 332 may be sized and configured to match a sizeand shape of the wiring or cabling for the electrodes 324, 326, and 328such that a sealing product is not necessary. Also, as shown in FIG. 9,the end mass 306 may include threads on an exterior surface of the endmass for engagement with a housing 302 of an ultrasonic transducerassembly and/or other component of a surgical instrument as describedherein.

Electrodes 324, 326, and 328 energize the piezoelectric elements 308a-308 d according to a drive signal received from a generator 102 basedon a predetermined wavelength and frequency of an ultrasonic wave inorder for a surgical instrument to apply ultrasonic energy to a target.Electrodes 324, 326, and 328 may have a shape that conforms to the shapeof a piezoelectric element 308 a-308 d to allow for maximum surface areacontact between a respective electrode 324, 326, and 328 andpiezoelectric elements 308 a-308 d. Electrodes 324, 326, and 328 arelocated at the proximal end of the ultrasonic transducer 304, closest tothe end mass 306, and the distal end of the ultrasonic transducer 304,respectively. Electrodes 324, 326, and 328 may be made from a conductivematerial, such as metal, for example, copper, that functions to providean electrical current to the piezoelectric elements 308 a-308 d.

As shown in FIG. 10, electrode 324 has a disk shape center 304 with anaperture 305 through the center. As shown in FIGS. 9 and 11, electrode328 comprises a disk shape center 404 with an aperture 405 and aplurality of arms 402 that extend outward from the center 404. The arms402 may be sized and configured to contact the inside walls of aconductive housing of a transducer assembly, such as housing 202described above, to provide an electrical ground for the ultrasonictransducer 304. Accordingly, the arms 402 may be configured to provide apath to ground or return to the generator 102. In addition, the arms 402provide an alignment feature for the transducer 304 as the transducer304 is placed into the housing 202. Further, electrodes 324 may providean electrical ground based on contact with the electrode 324 and thehousing 202 and the end mass 306, respectively. As shown in FIG. 12,electrode 326 comprises two contacts or pads 502 a-502 b, each with acenter 503 a-503 b with an aperture 505 a-505 b, where the contacts 502a-502 b are electrically connected together. The contacts 502 a-502 bare connected via an electrically conductive connection element 502 c. Awire or cable 506 is connected to one of the contacts 502 a-502 b forenergization of the contacts 502 a-502 b. The cable 506 may be coupledto the positive polarity (+) of the generator 102 output port. An apron504 is included for insulating the electrode 326 for electricallyisolating electrode 326 and preventing potential energization of otherelectrodes along with a housing of a surgical instrument.

Referring back to FIG. 9, when electrode 326 is energized, electricalcurrent may flow through the two piezoelectric elements 308 a-308 d inthe middle of the ultrasonic transducer stack 304 and follow a path toground, resulting in the energization of the piezoelectric element 308a-308 d at the proximal end of the ultrasonic transducer 304, closest tothe end mass 306, and the piezoelectric element 308 a-308 d at thedistal end of the ultrasonic transducer 304, respectively. Theelectrical current passing through the piezoelectric elements 308 a-308d causes the piezoelectric elements 308 a-308 d to expand and contract,which generates an ultrasonic wave.

FIG. 13 displays a cross sectional view of transducer assembly 300′ thatcomprises a housing 302′, ultrasonic transducer 304′, and end mass 306′.Similar to transducer assembly 200, the end mass 306′ compresses theultrasonic transducer 304′ within the horn shaped portion 320′ of thehousing 302′. Accordingly, the end mass 306′ may engage the horn shapedportion 320′ of the housing 302′ based on a threaded connection.Further, the housing 302′ comprises flange 316′. The flange 316′provides a location for attachment of a surgical instrument component342′ such as, for example, a surgical instrument housing that surroundsthe transducer assembly 300′, where a surgical instrument comprises thetransducer assembly 300′. In addition, the instrument component 342′ maycomprise an isolator that is intended to dampen or isolate thevibrations from the transducer assembly 300′. In one aspect, theisolator comprises an elastomer.

Aspects of the piezoelectric elements 308 a′-308 d′ are the same orsimilar to the piezoelectric elements 208 a-208 d of transducer assembly200 described with regard to FIGS. 5-8 above, as appropriate.Accordingly, the piezoelectric elements 308 a′-308 d′ may beelectrically connected in parallel and are paired in oppositedirections. A first electrode 309 b′ is disposed between adjacentpiezoelectric elements 308 a′-308 b′, a second electrode 309 c′ isdisposed between adjacent piezoelectric elements 308 b′-308 c′, and athird electrode 309 d′ is disposed between adjacent piezoelectricelements 308 c′-308 d′. A fourth electrode 309 a′ is disposed at theproximal end of the piezoelectric element 308 a′ and a fifth electrode309 e′ is disposed at the end of the piezoelectric element 308 d. In oneconfiguration, the electrodes 309 a-309 e′ are formed of an electricallyconductive material in thin disk configuration. The electrodes 309a′-309 e′ are configured to electrically couple to the generator 102(shown in FIGS. 1-3) to energize the piezoelectric elements 308 a′-308d′. In one configuration, the electrodes 309 a′, 309 c′, 309 e′ areconfigured to electrically couple to the negative polarity or return (−)of the generator 102 output port and the electrodes 309 b′, 309 d′ areconfigured to couple to the positive polarity (+) of the generator 102output port. In operation, the generator 102 applies an alternatingvoltage potential to the electrodes 309 a′-309 e′ to energize thepiezoelectric elements 308 a′-308 d′ and cause them to mechanicallyexpand and contract in the longitudinal direction in response to thealternating voltage potential. When the alternating voltage potential isin a frequency range of approximately 30-100 kHz, the alternatingvoltage potential causes the piezoelectric elements 308 a′-308 d′ tovibrate at ultrasonic frequencies. In one example, operational frequencyof the alternating voltage potential is approximately 55.5 kHz. In oneaspect, each of the electrodes 308 a′-308 d′ is a flat electrode.

In addition, according to the aspect shown in FIG. 13, the piezoelectricelements 308 a′-d′ and electrodes 309 a′-e′ comprise a borehole 328′therethrough that allows for insertion of an alignment feature 336′through the borehole 328′. The alignment feature 336′ is configured sothat the ultrasonic transducer 304′, and accordingly the piezoelectricelements 308 a′-d′ and electrodes 309 a′-e′, may be held in place withinthe horn shaped portion 320′ of the housing 302′. A gap 305′ ismaintained to prevent the ultrasonic transducer 304′ from shorting outagainst the housing 302′.

Additionally, the alignment feature 336′ comprises a post 336′ thatprovides structural support and allows for an energization of theappropriate electrodes 309 a′-309 e′. In one aspect, the post 336′comprises a lumen that is used for centering the transducer stack 304′during the torqueing of the end mass 306′ to the horn shaped portion320′ of the housing 302′. The lumen may have channels to allow wiresconnected to the electrodes 309 a′-309 e′ to be inserted in the centerof the lumen. The lumen may be removed after torqueing of the end mass306′ to the horn shaped portion 320′ is complete. This may improvealignment of the piezoelectric elements 308 a′-308 b′ and allow for verylow impedance (e.g. 12 ohms) electrodes/wiring to be used.

As shown in FIG. 13, a source or “hot” lead 332′ and a return or “cold”lead 334′ are connected to the post 336′. The source lead 332′ iscoupled to a generator, such as generator 102 described above, and toelectrodes 309 b′, 309 d′. The return lead 332′ is coupled to a groundconnection of or otherwise provides a return path to the generator, andis also coupled to electrodes 309 c′ and 309 e′. In aspects of thepresent disclosure, the source lead 332′ and/or the return lead 334′ maycomprise a wire that is located within the post 336′. Additionally, thepost 336′ may be made of a conductive material and may provide a returnpath for the electrodes 309 a′, 309 c′, and 309 e′. As shown in FIG. 13,the post 336′ of the alignment feature 330′ may extend into an indent oraperture in the housing 302′, which may allow the post 336′ to be heldin a secure engagement with the housing 302′. In one aspect, thealignment feature 330′ may be formed integrally with the end mass 306′and the end mass 306′ may be a solid object without an aperturetherethrough. In another aspect, the alignment feature 330′ may be aseparate component that fits through an aperture, such as borehole 328′,through the end mass 306′. In this aspect, a wire may extend through theborehole 328′ of the end mass 306′. The borehole 328′ and any openingsbetween the end mass 306′ and the housing 302′ may be covered with asealing product, such as solder, epoxy, glue, rubber, tape, or otherinsulation material, located therein to prevent the entry of foreignsubstances into the interior of the transducer assembly 300′. Inaddition, the alignment feature 330′ may comprise threads such that theultrasonic transducer 304′ or the individual piezoelectric elements 308a′-d′ and electrodes 309 a′-e′ can be threadedly engaged with thealignment feature 330′. In another aspect, the alignment feature 330′may rely on a compression fit between one of the ultrasonic transducer304′ or the individual piezoelectric elements 308 a′-d′ and theelectrodes 309 a′-e′.

Also as shown in FIG. 13, a return electrode 340′ is connected to theflange 316′ and the electrode 340′ is connected to a ground lead 338′(i.e. a ground wire) that provides a path to ground or return to thegenerator 102. The return electrode 340′ may have an outer diameter thatis shaped to match the geometry of flange 316′ and may have an innerdiameter that provides sufficient clearance to allow the returnelectrode 340′ to slip over an outer diameter of the horn shaped portion320′ of the housing 302′. In one aspect, inside the horn shaped portion320′, where the ultrasonic transducer stack 304′ resides, a return pathmay be established through the horn shaped portion 320′ to one or moreof the piezoelectric elements 308 a′-d′ and through the end mass 306′ toone or more of the piezoelectric elements 308 a′-d′.

FIGS. 14 and 15 display an aspect of an ultrasonic transducer assembly300 that includes an end mass 306, ultrasonic transducer stack 304, andhousing 302. The housing 302 comprises a flange 316. Similar to flange216, flange 316 may be annular around an exterior surface of the housing302 or it may include components at separate locations along theexterior surface of the housing 302. Aspects of the ultrasonictransducer stack 304 may be the same or similar to the ultrasonictransducer 204 described above, as appropriate. The ultrasonictransducer stack 304 comprises a plurality of piezoelectric elements ina stack configuration with a plurality of electrodes located in betweento energize the piezoelectric elements. Furthermore, any aspects of thehousing 302 may be the same or similar to the housing 202 describedabove, as appropriate.

As shown in FIG. 14, the end mass 306 has a channel 332 therethrough.The channel 332 may be used for the wiring or cabling that is connectedto one or more of the electrodes of the transducer stack 304 to allowfor energization of the electrodes 305 a-305 e and application ofelectricity to the piezoelectric elements 304 a-304 d. Aspects of theelectrodes 305 a-305 e and piezoelectric elements 304 a-304 d are thesame or similar to the piezoelectric elements 208 a-208 d and electrodes209 a-209 e of transducer assembly 200 described with regard to FIGS.5-8 above, as appropriate. The channel 332 may further have sealingproduct 334, such as solder, epoxy, glue, rubber, tape, or otherinsulation material, located within the channel or only at a proximalend, furthest from the transducer stack 304, to prevent the entry offoreign substances into the end mass 306 and ultrasonic transducer 304.Furthermore, while the end mass 306 may be threaded into the housing302, sealing product 334 is also located at a proximal end of the endmass 306 adjacent the location that the end mass 306 engages the housing302, such that the interior of the housing 302, along with thetransducer 304 and portion of the end mass 306 located within thehousing 302, is sealed and the end mass 306 is bonded to the housing302. In one aspect, the seal to the interior of the housing may be ahermetic seal. Further, in one aspect, any sections where the end mass306 engages the housing 302, along with the channel 332, may be weldedso that a seal is formed.

FIG. 16 displays a transducer assembly 600 similar to those discussedabove. The transducer assembly 600 comprises a housing 602, anultrasonic transducer stack 604, and an end mass 606. Any aspects of thehousing 602, transducer stack 604, and end mass 606 may have the same orsimilar attributes as any housing, ultrasonic transducer stack, and endmass described above, respectively, as appropriate. The transducer 604and end mass 606 may be positioned along a longitudinal axis 611. Thedistal end of the end mass 606 comprises a cap portion 627 that isconfigured to fit over a proximal rim 625 at the proximal end of thehorn shaped portion 620 of the housing 602. The cap portion 627 of theend mass 606 and the horn shaped portion 620 of the housing 602 act tohouse the transducer 604 and the cap portion 627 is designed to overlapwith the proximal rim 625 of the housing 602. In one aspect, there is agap between the end mass 606 and the housing 602 that provides a gapthat may be filled with aluminum wire for a laser welding process. Thethickness of the proximal rim 625 may be such that it is thinner than anadjacent portion of the housing 602. Furthermore, the thickness of theproximal rim 625 may be such that when the distal end of the end mass606 is placed over the proximal rim 625, the circumference of thehousing 602 and end mass 606 is uniform along the transducer assembly600. In one aspect, the transducer assembly 600 comprises a distal rim629, similar to the proximal rim 625. Additionally, the cap portion 627of the end mass 606 may be a length such that transducer 604 is held ata predetermined amount of compression when the end mass 606 is engagedwith the housing 602. The transducer 604 may be held in compression by afixed engagement or a bond at the distal end of the end mass 606 and theproximal end of the housing 602. The bond may be accomplished by anappropriate bonding means, such as an adhesive, a strap, a weld, such asa laser weld, around the circumference of the transducer assembly 600and a hermetic seal may be formed. By bonding the end mass 606 and thehousing 602, the ultrasonic transducer 604 may be held in compressionand remain under that compression even after the transducer assembly 600is activated a large number of times.

FIGS. 17 and 18 display photographs of a transducer assembly 700 similarto transducer assembly 600. The transducer assembly 700 comprises ahousing 702 and an end mass 706 that are made of aluminum and have beenwelded together via weld 734. A cable 735 is configured to pass throughan opening of the end mass 706 to provide electricity to an ultrasonictransducer (not shown) or to provide a reading of the voltage given offby the piezoelectric elements of the transducer. The transducer assembly700 may comprise an ultrasonic transducer, of which any aspects are thesame or similar to ultrasonic transducers 204 and 304 described above,as appropriate.

FIG. 19 displays a transducer assembly 800 that comprises a housing 802and an end mass 806. An annular groove or channel 842 is locatedadjacent a proximal end of the transducer assembly 800 on an exteriorsurface of the transducer assembly 800. An electrical contact 840 isconfigured to make contact with the groove 842 and provide an electricalcoupling between circuitry connected to the electrical contact 840 andthe exterior surface of the transducer assembly 800. In one aspect, theelectrical contact 840 comprises a pin, for example, such as a pogo pin.According to aspects, the transducer assembly 800 may be placed within asurgical instrument housing. The transducer assembly 800 may berotatable within the surgical instrument housing based on the relativemovement that is allowed between the electrical contact 840 and thetransducer assembly 800 based on the electrical connection between theexterior surface of the transducer assembly 800 and the electricalcontact 840. Any aspects of the housing 802 and end mass 806 may havethe same or similar attributes as a housing and an end mass describedabove, respectively, as appropriate. Further, any aspects of theultrasonic transducer that is located within the interior of transducerassembly 800, may be the same or similar to any ultrasonic transducersdescribed above, as appropriate. Accordingly, the electrical contact 840may provide a ground connection to a transducer stack where anelectrode, for example electrode 328, contacts the housing 802 of thetransducer assembly 800. In one aspect, the groove or channel 842 may belocated at a point where the end mass 806 and the housing 802 arebrought together. Therefore, the groove 842 may be formed based on aweld between the end mass 806 and the housing 802, where an electricallyconductive material, such as aluminum, is used for the weld. Further,the groove 842 may be formed in an exterior surface of either the endmass 806 or the housing 802.

FIG. 20 is a top view of the transducer assembly 900 that comprises ahousing 902, an ultrasonic transducer stack 904, and an end mass 906.Any aspects of the housing 902, transducer stack 604, and end mass 906may have the same or similar attributes as any housing, ultrasonictransducer stack, and end mass described above, respectively, asappropriate. The housing 902 also comprises a flange 916. Similar toflange 216 described above, flange 916 may be annular around an exteriorsurface of the housing 902 or it may include components at separatelocations along the exterior surface of the housing 902. Similar toultrasonic transducer 204 described above, the stack of piezoelectricelements 908 a-90 d consists of four solid disks as shown in FIG. 20 andcompression elements 910 are located at either end of the stack ofpiezoelectric elements 908 a-90 d. The compression element 910 maycomprise a metal compression plate or spacer that has a size and formfactor that corresponds to the piezoelectric elements 908 a-90 d. Thecompression element 910 may help to avoid damage to the stack ofpiezoelectric elements 908 a-90 d as the end mass 906 is threaded intoand engaged with the housing 902. The piezoelectric elements 908 a-908 dare electrically connected in parallel and are paired in oppositedirections. A first electrode 909 b is disposed between adjacentpiezoelectric elements 908 a-908 b, a second electrode 909 c is disposedbetween adjacent piezoelectric elements 908 b-908 c, and a thirdelectrode 909 d is disposed between adjacent piezoelectric elements 908c-908 d. A fourth electrode 909 a is disposed and at the proximal end ofthe piezoelectric element 908 a and a fifth electrode 909 e is disposedat the end of the piezoelectric element 908 d.

Further, the end mass 906 comprises torqueing feature 907 (e.g. hex head907) and an aperture 932 defined through the end mass 906. Additionally,the piston device 1000 shown in FIG. 21 and socket device 1100 shown inFIG. 22 may allow for pre-compression of the ultrasonic transducer 904and torqued engagement of the end mass 906 with the housing 902. Thepiston device 1000 feeds through the hollow socket head 1102 of thesocket device 1100. The hollow socket head 1102 contacts the hex head907 on the end mass 906 and torques the end mass 906. Aperture 932allows for the insertion of the piston head 1002 of piston device 1000.Piston device 1000 also comprises a load cell 1004 and actuator 1006.The actuator 1006 may be a linear actuator or a hydraulic actuator. Thepiston head 1002 is configured to apply a force against the ultrasonictransducer 904 within the housing 902. The piston head 1002 pushesagainst spacer 910, which is a non-piezoelectric component, to preventlocalized stress on the piezoelectric elements 908 a-90 d. When thepiston head 1002 applies sufficient pressure against the transducerstack 904, force is lower at the point of contact between the end mass906 and the transducer stack 904. With a lower force between the endmass 906 and the transducer 904, there is less friction and thereforeless torque applied to the transducer 904. As the end mass 906 istorqued into place within the housing 902, the force on the piston head1002 can be monitored. As the force on the piston head 1002 is reduced(e.g. caused by load sharing via the end mass 906), an operator may besignaled that the transducer 904 is at the correct pressure and theassembly step is finished.

FIG. 23 illustrates one aspect of an ultrasonic system 2300. Theultrasonic system 2300 may comprise an ultrasonic signal generator 2312coupled to an ultrasonic transducer assembly 2301 of a surgicalinstrument, referred to as a hand piece assembly 2360. The hand pieceassembly 2360 comprises a hand piece housing 2336, and an ultrasonicallyactuatable single element end effector or ultrasonically actuatableblade 2352. A housing 2302 of the ultrasonic transducer assembly 2301generally includes a transduction portion 2318, a first resonatorportion or end-bell 2320, and a second resonator portion or fore-bell2322, and ancillary components, such as flange 2316. The totalconstruction of these portions comprises a resonator. The ultrasonictransducer assembly 2301 is preferably an integral number of one-halfsystem wavelengths (n*λ/2: wherein “n” is any positive integer; e.g.,n=1, 2, 3 . . . ) in length. Further, the ultrasonic transducer assembly2301 comprises the ultrasonic transducer 2304, end mass 2306, andhousing 2302, where the housing 2302 comprises a nose cone 2326, avelocity transformer 2328, and a surface 2330. Aspects of the ultrasonictransducer assembly 2301 may be the same or similar as those describedabove with regard to transducer assemblies 200, 300, 600, 700, 800, and900, including the components thereto, as appropriate.

Further, the terms “proximal” and “distal” are used with reference to aclinician gripping the hand piece assembly 2360. Thus, the end effector2350 is distal with respect to the more proximal hand piece assembly2360. It will be further appreciated that, for convenience and clarity,spatial terms such as “top” and “bottom” also are used herein withrespect to the clinician gripping the hand piece assembly 2360. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and absolute.

The distal end of the end-bell 2320 is connected to the proximal end ofthe transduction portion 2318, and the proximal end of the fore-bell2322 is connected to the distal end of the transduction portion 2318.The fore-bell 2322 and the end-bell 2320 have a length determined by anumber of variables, including the thickness of the transduction portion2318, the density and modulus of elasticity of the material used tomanufacture the end-bell 2320 and the fore-bell 2322, and the resonantfrequency of the ultrasonic transducer assembly 2301. The fore-bell 2322may be tapered inwardly from its proximal end to its distal end toamplify the ultrasonic vibration amplitude as the velocity transformer2328, or alternately may have no amplification. A suitable vibrationalfrequency range may be about 20 Hz to 120 kHz. A well-suited vibrationalfrequency range may be about 30-100 kHz. One example operationalvibrational frequency may be approximately 55.5 kHz.

The ultrasonic transducer comprises an ultrasonic transducer stack 2304,aspects of which are the same or similar to any other ultrasonictransducer stack described herein. Positive and negative electrodes ofthe transducer stack 2304 are electrically coupled to wires 2338 and2340, respectively. The wires 2338 and 2340 are encased within a cable2342 and electrically connectable to the ultrasonic signal generator2312 of the ultrasonic system 2300. The ultrasonic transducer 2304 ofthe transducer assembly 2301 converts the electrical signal from theultrasonic signal generator 2312 into mechanical energy that results inprimarily a standing acoustic wave of longitudinal vibratory motion ofthe ultrasonic transducer 2304 and the end effector 2350 at ultrasonicfrequencies. In another aspect, the vibratory motion of the ultrasonictransducer may act in a different direction. For example, the vibratorymotion may comprise a local longitudinal component of a more complicatedmotion of the tip of the ultrasonic system 2300. When the transducerassembly 2301 is energized, a vibratory motion standing wave isgenerated through the transducer assembly 2301. The ultrasonic system2300 may be designed to operate at a resonance such that an acousticstanding wave pattern of a predetermined amplitude is produced. Theamplitude of the vibratory motion at any point along the transducerassembly 2301 may depend upon the location along the transducer assembly2301 at which the vibratory motion is measured. A minimum or zerocrossing in the vibratory motion standing wave is generally referred toas a node (e.g., where motion is usually minimal), and a local absolutevalue maximum or peak in the standing wave is generally referred to asan anti-node (e.g., where motion is usually maximal). According toaspects, the distance between an anti-node and its nearest node may beone-quarter wavelength (λ/4).

The wires 2338 and 2340 transmit an electrical signal from theultrasonic signal generator 2312 to the positive electrodes and thenegative electrodes of the ultrasonic transducer stack 2304. Thepiezoelectric elements 2308 are energized by the electrical signalsupplied from the ultrasonic signal generator 2312 in response to aswitch 2344 to produce an acoustic standing wave in the transducerassembly 2301. The switch 2344 may be configured to be actuated by aclinician's foot. The electrical signal causes the piezoelectricelements 2308 to expand and contract in a continuous manner along theaxis of the voltage gradient, producing longitudinal waves of ultrasonicenergy. The straining of the elements causes large alternatingcompressional and tensile forces within the material. These forces inthe piezoelectric elements 2308 manifest as repeated small displacementsresulting in large alternating compression and tension forces within thematerial. The repeated small displacements cause the piezoelectricelements 2308 to expand and contract in a continuous manner along theaxis of the voltage gradient, producing longitudinal waves of ultrasonicenergy. The ultrasonic energy is transmitted through the transducerassembly 2301 to the end effector 2350 via a transmission component orultrasonic transmission waveguide 2366. According to various aspects,the waveguide 2366, end effector 2350 and blade 2352 may all be referredto generally as the end effector 2350.

In order for the transducer assembly 2301 to deliver energy to the endeffector 2350, all components of the transducer assembly 2301 must beacoustically coupled to the end effector 2350. The distal end of theultrasonic transducer 2304 may be acoustically coupled at the surface2330 to the proximal end of the ultrasonic transmission waveguide 2366by a threaded connection such as a stud 2348. The components of thetransducer assembly 2301 are preferably acoustically tuned such that thelength of any assembly is an integral number of one-half wavelengths(n*λ/2), where the wavelength λ is the wavelength of a pre-selected oroperating longitudinal vibration drive frequency f_(d) of the transducerassembly 2301, and where n is any positive integer. It is alsocontemplated that the transducer assembly 2301 may incorporate anysuitable arrangement of acoustic elements.

The ultrasonic end effector 2350 may have a length substantially equalto an integral multiple of one-half system wavelengths (λ/2). A distalend or blade 2352 of the ultrasonic end effector 2350 may be disposednear an antinode in order to provide the maximum longitudinal excursionof the distal end. When the transducer assembly is energized, the distalend 2352 of the ultrasonic end effector 2350 may be configured to movein the range of, for example, approximately 10 to 500 micronspeak-to-peak, and preferably in the range of about 30 to 150 microns ata predetermined vibrational frequency.

The ultrasonic end effector 2350 may be coupled to the ultrasonictransmission waveguide 2366. The ultrasonic end effector 2350 and theultrasonic transmission guide 2364 as illustrated are formed as a singleunit construction from a material suitable for transmission ofultrasonic energy such as, for example, Ti6Al4V (an alloy of Titaniumincluding Aluminum and Vanadium), Aluminum, Stainless Steel, or othersuitable materials. Alternately, the ultrasonic end effector 2350 may beseparable (and of differing composition) from the ultrasonictransmission waveguide 2366, and coupled by, for example, a stud, weld,glue, quick connect, or other suitable known methods. The ultrasonictransmission waveguide 2366 may have a length substantially equal to anintegral number of one-half system wavelengths (λ/2), for example. Theultrasonic transmission waveguide 2366 may be preferably fabricated froma solid core shaft constructed out of material suitable to propagateultrasonic energy efficiently, such as the titanium alloy discussedabove, (e.g., Ti-6Al-4V) or any suitable aluminum alloy, or otheralloys, for example.

The ultrasonic transmission waveguide 2366 comprises a longitudinallyprojecting attachment post 2354 at a proximal end to couple to thesurface 2330 of the ultrasonic transmission waveguide 2366 by a threadedconnection such as the stud 2348. In the aspect illustrated in FIG. 23,the ultrasonic transmission waveguide 2366 comprises a plurality ofstabilizing silicone rings or compliant supports 2356 positioned at aplurality of nodes. The silicone rings 2356 dampen undesirable vibrationand isolate the ultrasonic energy from an outer sheath 2358 for assuringthe flow of ultrasonic energy in a longitudinal direction to the distalend 2352 of the end effector 2350 with maximum efficiency.

Also shown in FIG. 23, the outer sheath 2358 protects a user of theultrasonic instrument 2360 and a patient from the ultrasonic vibrationsof the ultrasonic transmission waveguide 2366. The sheath 2358 generallyincludes a hub 2362 and an elongated tubular member 2364. The tubularmember 2364 is attached to the hub 2362 and has an opening extendinglongitudinally therethrough. The sheath 2358 may be threaded or snappedonto the distal end of the hand piece housing 2336. The ultrasonictransmission waveguide 2366 extends through the opening of the tubularmember 2364 and the silicone rings 2356 isolate the ultrasonictransmission waveguide 2366 from the outer sheath 2358. The outer sheath2358 may be attached to the waveguide 2366 with an isolator pin (notshown). The hole in the waveguide 2366 may occur nominally at adisplacement. The waveguide 2366 may screw or snap onto the hand pieceassembly 2360 by the stud 2348. The flat portions of the hub 2362 mayallow the assembly to be torqued to a required level.

The hub 2362 of the sheath 2358 is preferably constructed from ULTEM®,and the tubular member 2364 is fabricated from stainless steel.Alternatively, the ultrasonic transmission waveguide 2366 may havepolymeric material surrounding it to isolate it from outside contact.The distal end of the ultrasonic transmission waveguide 2366 may becoupled to the proximal end of the end effector 2350 by an internalthreaded connection, preferably at or near an antinode. It iscontemplated that the end effector 2350 may be attached to theultrasonic transmission waveguide 2366 by any suitable means, such as awelded joint or the like. Although the end effector 2350 may bedetachable from the ultrasonic transmission waveguide 2366, it is alsocontemplated that the end effector 2350 and the ultrasonic transmissionwaveguide 2366 may be formed as a single unitary piece.

FIG. 24 illustrates one aspect of a hand piece assembly 2460, aspects ofwhich are the same or similar to hand piece assembly 2360, asappropriate. FIG. 24 shows a close in view of a portion of transducerassembly 2401, which includes housing 2402 and flange 2416, and a handpiece housing 2436 and nose cone 2426 of the hand piece assembly 2460.An electrode 2409 is located between the flange 2416 of the housing 2402and an isolator 2470. The isolator 2470 is used to dampen or isolate thevibrations from the transducer assembly 2401 to the hand piece assembly2460. In one aspect, the isolator 2470 comprises an elastomer.

The electrode 2409 is adjacent the flange 2416 and the electrode 2409 isconnected to a ground lead 2438 that provide a path to ground or returnto a generator that supplies power to the hand piece assembly 2460. Theelectrode 2409 may have an outer diameter that is shaped to match thegeometry of flange 2416 and may have an inner diameter that providessufficient clearance to allow the electrode 2409 to be placed over anouter surface the housing 2402. The electrical connection for the returnpath to the generator is intended to be through the outer surface of thetransducer. In one aspect, the electrode 2409 is a flat electrode thatis placed in contact with the flange 2416 and held in place by theisolator 2470.

FIGS. 25-26 illustrate one aspect of a transducer assembly 2500 and FIG.27 is an illustration of the housing 2502 of transducer assembly 2500shown in FIGS. 25-26. The transducer assembly comprises a housing 2502,an ultrasonic transducer 2504, and an end mass 2506. The housing 2502comprises a conduit section 2510 and a base portion 2520, wherein alumen or fluid passageway 2515 is defined through the conduit section2510 and the base portion 2520. The base portion 2520 is shown in FIGS.25-27 as having a horn shape, and may be referred to as a horn-shapedportion 2520. The transducer assembly 2500 may also include a conductiveelement 2514, insulator 2512, and the conduit section 2510 of thehousing 2502. An inner isolator region may be present based on insulator2512 that provides a nonconductive path between the conduit section 2510of the housing 2502 and the conductive element 2514. The housing 2502may be at ground or low potential and provide a return path to thegenerator 102. The conductive element 2514 may be connected to a highpotential from the generator 102.

As shown in more detail in FIGS. 28-29, conductive element 2514 may bepositioned so that it surrounds the conduit section 2510 of the housing2502 and is electrically isolated from the conduit section 2510.According to aspects, the conductive element 2514 may completely or atleast partially surround the conduit section 2510. Further, insulator2512 may be positioned and held in place between the conductive element2514 and the conduit section 2510. As shown in FIG. 29, a feature suchas an external annular ring 2528, such as for example, an o-ring made ofrubber or plastic or a raised edge of material, may be present to holdthe conductive element 2514 in a desired location and to provide a sealbetween the insulator 2512 and the conductive element 2514. Theconductive element 2514 may be formed as a tube that is sized andconfigured to fit around the insulator 2512 and conduit section 2510 ofthe housing 2502. The conductive element 2514 may be made of aconductive material, such as copper, aluminum, steel, or other materialas appropriate. The conductive element 2514 provides both isolation anda conductive path for high potential to the appropriate electrodes 2509a-2509 e. In one aspect, each of the electrodes 2509 a-2509 e is a flatelectrode. Accordingly, in the aspect shown in FIG. 26, the conductiveelement 2514 allows for energization of piezoelectric elements 2508a-2508 d via the electrodes 2509 b and 2509 d as described in moredetail below. The insulator 2512 may also be formed as a tube that issized and configured to fit around the conduit section 2510 of thehousing 2502. The insulator 2512 may be made of an insulating material,such as fiberglass, plastic, rubber, or other material as appropriate.

The ultrasonic transducer 2504 comprises a plurality of piezoelectricelements 2508 a, 2508 b, 2508 c, 2508 d arranged in a stackconfiguration, which may be referred to as a “Langevin stack”. Alongitudinal axis 2511 forms a centerline of the piezoelectric elements2508 a-2508 d. A borehole 2527 is defined through the ultrasonictransducer 2504 and the end mass 2506 is positioned along thelongitudinal axis 2511 adjacent a first end of the ultrasonic transducer2504. The end mass 2506 also comprises a borehole 2527. The conduitsection 2510 of the housing 2502, along with the insulator 2512 andconductive element 2514, is configured to pass through the boreholes2527 in the ultrasonic transducer 2504 and end mass 2506. This providesan alignment feature for the ultrasonic transducer 2504 as the end mass2506 is placed over the ultrasonic transducer 2504 and engaged with thehousing 2502. The ultrasonic transducer 2504 may then be held inposition in the interior compartment formed by the end mass 2506 andhousing 2502 and spaced properly from the others components of theassembly 2500 so that arcing and/or shorting out of the electrode andconductive element does not occur. Furthermore, the end mass 2506 isconfigured to compress an end of the ultrasonic transducer 2504 againstthe interior surface 2528 of the housing 2502 when the end mass 2506 isengaged with the housing 2502.

In one aspect, the stack of piezoelectric elements 2508 a-2508 dcomprises four disks made of a lead zirconate titanate (PZT) materialcontained in a compression housing. In other aspects, the ultrasonictransducer 2504 piezoelectric stack may comprise an even multiple (n×2)of piezoelectric elements. The piezoelectric stack may be assembled wet(glue bonded) directly onto the threaded end mass 2506 and equipped withelectrically conducive elements such as wires or cables, for example, toconnect the piezoelectric stack to an active energy source and ground atthe generator 102 (FIGS. 1-3). Accordingly, the end mass 2506 andultrasonic transducer 2504 may be separate components that are thenbonded together to allow for assembly of the transducer assembly 2500.The piezoelectric elements 2508 a-2508 d are electrically connected inparallel and are paired in opposite directions. A first electrode 2509 bis disposed between adjacent piezoelectric elements 2508 a-2508 b, asecond electrode 2509 c is disposed between adjacent piezoelectricelements 2508 b-2508 c, and a third electrode 2509 d is disposed betweenadjacent piezoelectric elements 2508 c-2508 d. A fourth electrode 2509 ais disposed and at the proximal end of the piezoelectric element 2508 aand a fifth electrode 2509 e is disposed at the end of the piezoelectricelement 2508 d. In one configuration, the electrodes 2509 a-2509 e areformed of an electrically conductive material in thin diskconfiguration. The electrodes 2509 a-2509 e are configured toelectrically couple to the generator 102 (shown in FIGS. 1-3) toenergize the piezoelectric elements 2508 a-2508 d.

In one configuration, the electrodes 2509 a, 2509 c, 2509 e areconfigured to electrically couple to the negative polarity or return (−)of the generator 102 output port and the electrodes 2509 b, 2509 d areconfigured to electrically couple to the positive polarity (+) of thegenerator 102 output port. Electrodes 2509 a, 2509 c, 2509 e form areturn path to the generator based on contact with the end mass 2506 andthe housing 2502. As shown in FIG. 26, electrodes 2509 a and 2509 e arein contact with an interior surface of the end mass 2506 and an interiorsurface of the housing 2502, respectively, when the ultrasonictransducer 2504 is held in compression by the engagement of the end mass2506 and housing 2502. Further, electrode 2509 c is in contact with thewall 2517 of the end mass 2506 based on the tabs 2526 on electrode 2509c. Electrodes 2509 b and 2509 d form a path to the positive polarity ofthe generator 102 output port based on contact between the tabs 2524 ofeach electrode 2509 b, 2509 d and the conductive element 2514. The tabs2524 and 2526 of the electrodes 2509 b, 2509 d, 2509 c may be sized andconfigured so that they hold the ultrasonic transducer 2504 at aspecific distance from the surfaces with the end mass 2506 and housing2502 and provide for a secure fit. According to aspects, the tabs 2524and 2526 may be held in contact with the conductive element or othersurface as appropriate based on the tension of material of the tabs.

In operation, the generator 102 applies an alternating voltage potentialto the electrodes 2509 a-2509 e to energize the piezoelectric elements2508 a-2508 d and cause them to mechanically expand and contract in thelongitudinal direction in response to the alternating voltage potential.When the alternating voltage potential is in a frequency range ofapproximately 30-100 kHz, the alternating voltage potential causes thepiezoelectric elements 2508 a-2508 d to vibrate at ultrasonicfrequencies. In one example, operational frequency of alternatingvoltage potential is approximately 55.5 kHz. Further, in one aspect, thetransducer assembly is configured to resonate at 40 kHz. Additionally,in one aspect, the ultrasonic transducer 2504 may comprise compressionelements, similar to or the same as compression elements 210 discussedabove, located at the ends of the piezoelectric elements 2508 a and 2508d.

As shown in FIG. 26, the end mass 2506 has a distal portion having anopening 2513 defined therein for receiving the ultrasonic transducer2504 and a wall 2517 that surrounds and houses the ultrasonic transducer2504 when it is inserted into the opening 2513 defined by the distalportion of the end mass 2506. The end mass 2506 may include internalthreads on an inner wall surface allowing for the end mass 2506 to betorqued into place with respect to the housing 2502. The horn shapedportion 2520 of the housing 2520 may serve the function of amplifyingthe displacement of the ultrasonic transducer 2504, and thepiezoelectric elements 2508 a-2508 d of the ultrasonic transducer 2504are configured to be compressed against the interior surface 2528 of thehorn shaped portion 2520 of the housing 2502. According to variousaspects, the diameter of the ultrasonic transducer 2504 may be smallerthat the inner diameter of the end mass 2506. Accordingly, a gap 2505may be defined between the ultrasonic transducer 2504 and the interiorof the end mass 2506. This allows for insertion of the ultrasonictransducer 2504 and prevents the piezoelectric elements 2508 a-2508 dfrom coming into unwanted contact with an interior surface of the wall2517 of the end mass 2506.

Moreover, the end mass 2506 comprises a flange 2516. The flange 2516 isshown as an annular ring around the perimeter of the end mass 2506.However, the flange 2516 may be positioned in sections located about theperimeter instead of arranged as a continuous ring. In other aspects,there may be additional flanges similar to and in addition to the flange2516 located at predetermined locations on the end mass 2506 and/or thehousing 2502. Further, the flange 2516 may be located at other locationsalong the end mass 2506 or the housing 2502. For example, the flange2516 may be located along the housing 2502 closer to a distal end of thehousing 2502. According to various aspects, the flange 2516 may includean O-ring or other elastomeric material member (not shown) that mayprovide sealing as well as damping of vibrations within the flange 2516and the end mass 2506 overall. An o-ring may be mounted within a grooveor other feature (not shown) of the flange 2516. Also, according tovarious aspects, the flange 2516 may be replaced with a mass havingradial dimensions similar to those of the ultrasonic transducer 2504 andthe end mass 2506. A hand piece housing, or other frame member, of asurgical instrument may include corresponding shapes for receiving theflange 2516.

The corresponding engagement of the end mass 2506 and horn shapedportion 2520 of the housing 2502 allows for easier assembly of thetransducer assembly 2500 and provides advantages in heat dissipation andpotential sealing of the ultrasonic transducer 2504 and the stack ofpiezoelectric elements 2508 a-2508 d. In other aspects, the end mass2506 may be threaded on an outside surface in a manner that matches thethreads on the horn shaped portion 2520. This enables the horn shapedportion 2520 to fit over the end mass 2506 while compressing theultrasonic transducer 2504 within the interior of the end mass 2506. Theend mass 2506 may engage with the housing 2502 based on any appropriateconnection. For example, in one aspect, the end mass 2506 has anattachment surface and the housing 2502 has an attachment surface withcorresponding threads for engaging the end mass 2506 and the horn shapedportion 2520. In another aspect, the end mass 2506 may be adhered to thehousing 2502 using a glue or epoxy of appropriate strength. In stillanother aspect, the end mass 2506 and housing may be welded together.Furthermore, the engagement between the end mass 2506 and the housing2502 may comprise a seal to prevent foreign materials from entering thearea in which the ultrasonic transducer is located.

In addition, the housing 2502 may comprise an attachment end 2522 forattaching a waveguide section or other instrument section. Theattachment end 2522 may be threaded or may include a quick connectand/or a locking feature for attachment of other components thereto. Invarious aspects, the housing 2502 and/or the end mass 2506 each may beconstructed as a unitary piece or in sections. Further, the housing 2502and the end mass 2506 each may be made from a type of metal that isappropriate for the application of the transducer assembly, for example,such as aluminum, stainless steel, titanium, and/or alloys thereof. Inother aspects, the housing 2502 may be constructed from other materials,such as carbon fiber, fiberglass, plastic, etc. as appropriate.

As shown in FIG. 27, the housing 2502 comprises a conduit section 2510and a base portion 2520. The base portion 2520 may comprise a firstsection 2530 having a first diameter, a second section 2532 that tapersfrom the first diameter to a second diameter, and a third section 2534having the second diameter. The attachment end 2522 may have a thirddiameter that allows for attaching a waveguide section or otherinstrument section. The first section 2530 may also comprise threads(not shown) that correspond to threads on the end mass 2506 that allowfor threaded engagement between the housing 2502 and end mass 2506.Additionally, the interior surface 2528 corresponds to the firstdiameter of the first section 2530 of the base portion 2520. Theinterior surface 2528 is sized and configured to correspond to the sizeand shape of an electrode of the ultrasonic transducer 2504. Theinterior surface 2528 may match the surface area of the electrode toprovide a contact surface and electrical coupling between the electrodeand the housing 2502. The lumen or fluid passageway 2515 is definedthrough the conduit section 2510 and the base portion 2520, so thatfluid can pass through the entire housing 2502. According to aspects,the housing 2502 may be constructed as a single component with no gaps,seams, etc., enabling ease of cleaning, sanitizing, etc. of the housing2502. While the base portion 2520 of the housing 2502 has a horn shapeshown in FIGS. 25-27, according to other aspects, the housing 2502 mayhave other shapes and configurations. For example, in one aspect, thehousing 2502 may not have a tapered second section 2532. Instead, atransition in the base portion 2520 may comprise an abrupt changebetween two different diameters of first section 2530 and third section2534, respectively, while still having the fluid passageway 2515 definedtherethrough.

Referring back to FIG. 26, the end mass 2506 may be coupled to theultrasonic transducer 2504 and the end mass 2506 may be fixedly orremovably attached with the housing 2502. In one aspect, the ultrasonictransducer 2504 is coupled or bonded to the end mass 2506. Theultrasonic transducer 2504 and the end mass 2506 or the ultrasonictransducer 2504 and the housing 2502 may be bonded together via anadhesive, a weld, or other suitable bonding mechanism. In the aspectshown in FIGS. 25-27, the end mass 2506 is configured to compress an endof the plurality of piezoelectric elements 208 a-208 d against aninterior, distal surface of the end mass 2506 and to compress anotherend of the plurality of piezoelectric elements 208 a-208 d against theinterior, proximal surface 2528 of the housing 2502 when the end mass2506 is engaged with the housing 2502. The end mass 2506 may beconfigured to engage with the housing 2502 via a threaded connection.When the end mass 2506 is engaged with the housing 2502, a second end ofthe ultrasonic transducer 204 is compressed against an interior surfaceof the end mass 2506. According to aspects, the end mass 2506 may alsoinclude one or more channels to allow for wiring to be connected to theultrasonic transducer 2504. These channels may allow for ultrasonictransducer 2504 to be energized without the use of conductive element2514. In addition, as shown in FIGS. 25-26, the end mass 2506 maycomprise a proximal torqueing feature 2507 a that allows torque to beapplied to the end mass 2506. The torqueing feature 2507 a includes foursmooth surfaces. In other aspects, the torqueing feature 2507 a may beany type of drive that allows for torqueing the end, for example anytype of screw drive. Furthermore, according to the aspect shown in FIGS.25-27, the housing 2502 may also comprise a distal torqueing feature2507 b, similar to the proximal torqueing feature 2507 a, which also mayinclude four smooth surfaces.

Similar to the piezoelectric elements 208 a-208 d described above, thepiezoelectric elements 2508 a-2508 d may be fabricated from any suitablematerial, such as, for example, lead zirconate-titanate (PZT), leadmeta-niobate, lead titanate, barium titanate or other piezoelectricceramic material. As shown in FIG. 26, each of the piezoelectricelements 2508 a-2508 d have a annular or ring-shaped configuration andare formed as an element with an aperture defined therethrough. Inaddition, the piezoelectric elements 2508 a-2508 d comprise a borehole2527 through each element that allows for assembly of other features ofthe ultrasonic transducer 2504. In other aspects, the piezoelectricelements 2508 a-2508 d may have a different shape, different surfacecharacteristics, such as additional apertures for bonding a plurality ofelements together, and the elements may have an appropriate aspectfactor for a particular application. Additionally, the piezoelectricelements 2508 a-2508 d may be energized via positive electrodes 2509 b,2509 d and negative electrodes 2509 a, 2509 c, 2509 e positioned betweenthe piezoelectric elements 2508 a-2508 d and at the ends of thepiezoelectric elements 2508 a and 2508 e as shown in FIG. 26. Thepositive and negative electrodes 2509 a-2509 e may be electricallycoupled to wires via conductive element 2514 and the wires may beencased within a cable and electrically connectable to an ultrasonicsignal generator of an ultrasonic system as described above. Some or allof the electrodes 2509 a-2509 e may be the same as or similar toelectrodes 209 a-209 e described previously.

As shown in FIG. 26, each of positive electrodes 2509 b, 2509 d,negative electrodes 2509 a, 2509 c, 2509 e, and the piezoelectricelements 2508 a-2508 d that make up the ultrasonic transducer 2504, eachhave a borehole 2527 extending therethrough. The ultrasonic transducer204 of the transducer assembly 2500 is configured to convert anelectrical signal from an ultrasonic generator, such as generator 102described above in connection with FIGS. 1-3, into mechanical energythat results in primarily a standing acoustic wave of longitudinalvibratory motion of the ultrasonic transducer 2504 and an end effector(not shown in FIGS. 25-26) at ultrasonic frequencies. In another aspect,the vibratory motion of the ultrasonic transducer 2504 may act in adifferent direction. For example, the vibratory motion may comprise alocal longitudinal component of a more complicated motion of the tip ofthe ultrasonic instrument. When the transducer assembly 2500 isenergized, a vibratory motion standing wave may be generated through thetransducer assembly 2500. The transducer assembly 2500 may be designedto operate at a resonance such that an acoustic standing wave pattern ofa predetermined amplitude is produced. The amplitude of the vibratorymotion at any point along the transducer assembly 2500 may depend uponthe location along the transducer assembly 200 at which the vibratorymotion is measured. A minimum or zero crossing in the vibratory motionstanding wave is generally referred to as a node (e.g., where motion isusually minimal), and a local absolute value maximum or peak in thestanding wave is generally referred to as an anti-node (e.g., wheremotion is usually maximal). According to aspects, the distance betweenan anti-node and its nearest node may be one-quarter wavelength (λ/4).

Furthermore, the plurality of piezoelectric elements 2508 a-2508 d andelectrodes 2509 a-e may be bonded via an adhesive, such as with an epoxyor other glue, a weld, or other suitable bonding mechanism. In oneaspect, surfaces of a piezoelectric element 2508 a-2508 d may have anadhesive, such as epoxy, placed on it and then an electrode may beplaced over the adhesive. The adhesive may be provided in a layer suchthat it does not interfere with the electrical connections between theelectrodes 2509 a-2509 e and the piezoelectric elements 2508 a-2508 dand the piezoelectric elements 2508 a-2508 d themselves. Further,according to aspects, only some of the piezoelectric elements 2508a-2508 d may be bonded together, instead of the entire number ofpiezoelectric elements 2508 a-2508 d. In addition, the plurality ofpiezoelectric elements 2508 a-2508 d may be assembled dry, with noadhesive or bonding mechanism between each of the layers. Additionally,any openings or spacing between the conductive element 2514 and theborehole 2527 through the end mass 2506 may have sealing product, suchas solder, epoxy, glue, rubber, or other insulation material, locatedtherein to prevent the entry of foreign substances into the interiorcompartment formed by the engagement of end mass 2506 and housing 2502.

FIGS. 30 and 31 illustrate aspects of electrodes 3002 and 3008,respectively. As shown in FIG. 30, electrode 3002 comprises an annularshaped surface 3001 with an outer edge 3005 and an aperture that definesan inner edge 3007 of the electrode 3002. Electrode 3002 furthercomprises a plurality of tabs 3003 that extend inward towards the centerof the electrode 3002. As shown in FIG. 31, similar to electrode 3002,electrode 3008 comprises an annular shaped surface 3001 with an outeredge 3005 and an aperture that defines an inner edge 3007 of theelectrode 3008. Electrode 3008 further comprises a plurality of tabs3009 that extend outward, away from the center of the electrode 3008.The electrode tabs 3003 and 3009 serve to provide both an electricalconductivity path as well as a centering function during the process ofconstructing the transducer assembly 2500. Accordingly, the tabs 3003may be sized and configured to contact the conductive element 2514 toprovide for electrical energization of the piezoelectric elements 2508a-2508 d of the ultrasonic transducer 2504. Additionally, tabs 3009 maybe sized and configured to contact the inside surface of the wall of theend mass 2506, to provide an electrical ground for the ultrasonictransducer 2504. In one aspect, each of tabs 3003, 3009, can be twistedduring construction of the transducer assembly 2500, such that thecontacting edge/region of a tab aligns more favorably with the motion ofthe contacting surface of the mating part during assembly of thetransducer assembly 2500.

FIG. 32 provides an illustration of the contact made between the tabs3003 of electrode 3002 and conductive element 2514 during assembly ofthe components. One or more of tabs 3003 may have solder 3010 presentthereon, to establish an electrical connection between the electrode3002 and the conductive element 2514. In one aspect, the solder 3010 maybe placed on the tab 3003 after the electrode 3002 has been put intoplace, for example, by twisting the electrode 3002 over the conductiveelement 2514, at a location along the conductive element 2514. Inanother aspect, the tab 3003 may be pre-soldered, such that the solder3010 is placed on the tab 3003 prior to assembly of the electrode 3002and conductive element 2514. The solder 3010 may be heated, for example,during a reflow soldering process or by direct heating applied to thesolder, to complete a connection. According to aspects, tabs 3009 ofelectrode 3008 may be pre-soldered and connected to a surface in thesame or similar fashion. In one aspect, solder may be used where thecontact pressure between the conductive element or other surface and theelectrode tabs 3003, 3009 becomes insufficient, and the tabs 3003, 3009could be pre-soldered, installed, and necessary heat applied to theconductive element or other surface to melt the solder and make agas-tight connection.

While various details have been set forth in the foregoing description,it will be appreciated that the various aspects of the surgical systemwith user adaptable techniques employing simultaneous energy modalitiesbased on tissue parameters may be practiced without these specificdetails. For example, for conciseness and clarity, selected aspects havebeen shown in block diagram form rather than in detail. Some portions ofthe detailed descriptions provided herein may be presented in terms ofinstructions that operate on data that is stored in a computer memory.Such descriptions and representations are used by those skilled in theart to describe and convey the substance of their work to others skilledin the art. In general, a technique refers to a self-consistent sequenceof steps leading to a desired result, where a “step” refers to amanipulation of physical quantities which may, though need notnecessarily, take the form of electrical or magnetic signals capable ofbeing stored, transferred, combined, compared, and otherwisemanipulated. It is common usage to refer to these signals as bits,values, elements, symbols, characters, terms, numbers, or the like.These and similar terms may be associated with the appropriate physicalquantities and are merely convenient labels applied to these quantities.

Unless specifically stated otherwise as apparent from the foregoingdiscussion, it is appreciated that, throughout the foregoingdescription, discussions utilizing terms such as “processing” or“computing” or “calculating” or “determining” or “displaying” or thelike, refer to the action and processes of a computer system, or similarelectronic computing device, that manipulates and transforms datarepresented as physical (electronic) quantities within the computersystem's registers and memories into other data similarly represented asphysical quantities within the computer system memories or registers orother such information storage, transmission or display devices.

It is worthy to note that any reference to “one aspect,” “an aspect,”“one aspect,” or “an aspect” means that a particular feature, structure,or characteristic described in connection with the aspect is included inat least one aspect. Thus, appearances of the phrases “in one aspect,”“in an aspect,” “in one aspect,” or “in an aspect” in various placesthroughout the specification are not necessarily all referring to thesame aspect. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreaspects.

Some aspects may be described utilizing the expression “coupled” and“connected” along with their derivatives. It should be understood thatthese terms are not intended as synonyms for each other. For example,some aspects may be described utilizing the term “connected” to indicatethat two or more elements are in direct physical or electrical contactwith each other. In another example, some aspects may be describedutilizing the term “coupled” to indicate that two or more elements arein direct physical or electrical contact. The term “coupled,” however,also may mean that two or more elements are not in direct contact witheach other, but yet still co-operate or interact with each other.

Although various aspects have been described herein, many modifications,variations, substitutions, changes, and equivalents to those aspects maybe implemented and will occur to those skilled in the art. Also, wherematerials are disclosed for certain components, other materials may beused. It is therefore to be understood that the foregoing descriptionand the appended claims are intended to cover all such modifications andvariations as falling within the scope of the disclosed aspects. Thefollowing claims are intended to cover all such modification andvariations.

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., aspects of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment). Those having skill in the art will recognize that thesubject matter described herein may be implemented in an analog ordigital fashion or some combination thereof.

The foregoing detailed description has set forth various aspects of thedevices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In one aspect, severalportions of the subject matter described herein may be implemented viaApplication Specific Integrated Circuits (ASICs), Field ProgrammableGate Arrays (FPGAs), digital signal processors (DSPs), or otherintegrated formats. However, those skilled in the art will recognizethat some forms of the aspects disclosed herein, in whole or in part,can be equivalently implemented in integrated circuits, as one or morecomputer programs running on one or more computers (e.g., as one or moreprograms running on one or more computer systems), as one or moreprograms running on one or more processors (e.g., as one or moreprograms running on one or more microprocessors), as firmware, or asvirtually any combination thereof, and that designing the circuitryand/or writing the code for the software and or firmware would be wellwithin the skill of one of skill in the art in light of this disclosure.In addition, those skilled in the art will appreciate that themechanisms of the subject matter described herein are capable of beingdistributed as a program product in a variety of aspects, and that anillustrative aspect of the subject matter described herein appliesregardless of the particular type of signal bearing medium used toactually carry out the distribution. Examples of a signal bearing mediuminclude, but are not limited to, the following: a recordable type mediumsuch as a floppy disk, a hard disk drive, a Compact Disc (CD), a DigitalVideo Disk (DVD), a digital tape, a computer memory, etc.; and atransmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunications link, a wireless communication link (e.g., transmitter,receiver, transmission logic, reception logic, etc.), etc.).

All of the above-mentioned U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications, non-patent publications referred to in this specificationand/or listed in any Application Data Sheet, or any other disclosurematerial are incorporated herein by reference, to the extent notinconsistent herewith. As such, and to the extent necessary, thedisclosure as explicitly set forth herein supersedes any conflictingmaterial incorporated herein by reference. Any material, or portionthereof, that is said to be incorporated by reference herein, but whichconflicts with existing definitions, statements, or other disclosurematerial set forth herein will only be incorporated to the extent thatno conflict arises between that incorporated material and the existingdisclosure material.

One skilled in the art will recognize that the herein describedcomponents (e.g., operations), devices, objects, and the discussionaccompanying them are used as examples for the sake of conceptualclarity and that various configuration modifications are contemplated.Consequently, as used herein, the specific exemplars set forth and theaccompanying discussion are intended to be representative of their moregeneral classes. In general, use of any specific exemplar is intended tobe representative of its class, and the non-inclusion of specificcomponents (e.g., operations), devices, and objects should not be takenlimiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely examples and that in fact many other architectures may beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated also can be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated also can be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents, and/or wirelessly interactable, and/or wirelesslyinteracting components, and/or logically interacting, and/or logicallyinteractable components.

In some instances, one or more components may be referred to herein as“configured to,” “configurable to,” “operable/operative to,”“adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Thoseskilled in the art will recognize that “configured to” can generallyencompass active-state components and/or inactive-state componentsand/or standby-state components, unless context requires otherwise.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be apparent to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from the subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of the subject matter described herein.It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flows are presented in asequence(s), it should be understood that the various operations may beperformed in other orders than those which are illustrated, or may beperformed concurrently. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Furthermore, terms like“responsive to,” “related to,” or other past-tense adjectives aregenerally not intended to exclude such variants, unless context dictatesotherwise.

Although various aspects have been described herein, many modifications,variations, substitutions, changes, and equivalents to those aspects maybe implemented and will occur to those skilled in the art. Also, wherematerials are disclosed for certain components, other materials may beused. It is therefore to be understood that the foregoing descriptionand the appended claims are intended to cover all such modifications andvariations as falling within the scope of the disclosed aspects. Thefollowing claims are intended to cover all such modification andvariations.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more aspects has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise aspect disclosed. Modifications or variations are possible inlight of the above teachings. The one or more aspects were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousaspects and with various modifications as are suited to the particularuse contemplated. It is intended that the claims submitted herewithdefine the overall scope.

Various aspects of the subject matter described herein are set out inthe following numbered examples:

EXAMPLE 1

A surgical instrument for coagulating and dissecting tissue, thesurgical instrument comprising: a transducer assembly comprising:

a housing;

an ultrasonic transducer comprising a plurality of piezoelectricelements and a plurality of electrodes arranged in a stackconfiguration, wherein an electrode is located between each pair ofsolid piezoelectric elements;

an end mass positioned adjacent a first end of the ultrasonictransducer, wherein the end mass is configured to engage with thehousing; and

wherein the end mass is configured to compress the ultrasonic transduceragainst an interior surface of the housing when the end mass is engagedwith the housing.

EXAMPLE 2

The surgical instrument of Example 1, wherein the plurality ofpiezoelectric elements have a longitudinal axis and the end mass has alongitudinal axis that is aligned with the longitudinal axis of theplurality of piezoelectric elements.

EXAMPLE 3

The surgical instrument of Example 1 or 2, wherein the housing comprisesa portion having an opening defined therein, wherein the ultrasonictransducer is configured to fit within the portion of the housing andthe end mass is configured to engage with the housing via a threadedconnection between the end mass and the portion of the housing.

EXAMPLE 4

The surgical instrument of any one or more of Example 1 through Example3, wherein at least one of the plurality of piezoelectric elements is asolid piezoelectric element.

EXAMPLE 5

The surgical instrument of any one or more of Example 1 through Example4, wherein the stack configuration further comprises:

a first electrode located at a first end of the stack configuration andin contact with one surface of a first piezoelectric element; and

a second electrode located at a second end of the stack configurationand in contact with one surface of a second piezoelectric element.

EXAMPLE 6

The surgical instrument of any one or more of Example 1 through Example5, further comprising an alignment feature configured to provide a gapbetween the plurality of piezoelectric elements and a side wall of theinterior surface of the housing.

EXAMPLE 7

The surgical instrument of any one or more of Example 1 through Example6, wherein the end mass comprises a torqueing feature that allows torqueto be applied to the end mass.

EXAMPLE 8

The surgical instrument of any one or more of Example 1 through Example7, wherein the transducer assembly is configured to resonate at 40 kHz.

EXAMPLE 9

The surgical instrument of any one or more of Example 1 through Example8, wherein the end mass is configured to engage with the housing via athreaded connection.

EXAMPLE 10

The surgical instrument of any one or more of Example 1 through Example9, wherein a first piezoelectric element of the plurality ofpiezoelectric elements and a second piezoelectric element of theplurality of piezoelectric elements are electrically connected inparallel.

EXAMPLE 11

The surgical instrument of any one or more of Example 1 through Example10, wherein the ultrasonic transducer is sealed within the housing.

EXAMPLE 12

The surgical instrument of any one or more of Example 1 through Example11, wherein the end mass is bonded to the housing to create a sealaround the interior surface of the housing.

EXAMPLE 13

The surgical instrument of any one or more of Example 1 through Example12, further comprising an electrical contact that is configured toelectrically couple to an exterior surface of the housing.

EXAMPLE 14

The surgical instrument of any one or more of Example 1 through Example13, further comprising a surgical instrument housing, wherein thetransducer assembly is located with the surgical instrument housing andis configured to be rotatable within the surgical instrument housing.

EXAMPLE 15

The surgical instrument of any one or more of Example 1 through Example14, further comprising a spacer element, wherein the spacer element islocated at a first end of the stack configuration and wherein a firstend of the end mass contacts the spacer element when the end masscompresses the ultrasonic transducer.

EXAMPLE 16

The surgical instrument of any one or more of Example 1 through Example15, wherein, when the end mass compresses the ultrasonic transduceragainst the interior surface of the housing, the first end of theultrasonic transducer contacts a first end of the end mass and a secondend of the ultrasonic transducer is compressed against the interiorsurface of the housing.

EXAMPLE 17

The surgical instrument of any one or more of Example 1 through Example16, wherein at least one of the plurality of piezoelectric elements is asolid piezoelectric element having a disk shape.

EXAMPLE 18

A surgical instrument for coagulating and dissecting tissue, thesurgical instrument comprising:

a transducer assembly comprising:

-   -   a housing;    -   an ultrasonic transducer comprising a plurality of solid        piezoelectric elements and a plurality of electrodes arranged in        a stack configuration having a longitudinal axis, a first end,        and a second end, wherein an electrode is located between each        pair of solid piezoelectric elements, an electrode is located at        the first end of the stack configuration, and an electrode is        located at the second end of the stack configuration;    -   an end mass positioned along the longitudinal axis adjacent a        first end of the ultrasonic transducer and coupled to the        ultrasonic transducer, wherein the end mass is configured to        engage with the housing; and    -   wherein the end mass is configured to compress the ultrasonic        transducer against an interior surface of the housing when the        end mass is engaged with the housing; and    -   wherein a first solid piezoelectric element of the plurality of        solid piezoelectric elements and a second solid piezoelectric        element of the plurality of solid piezoelectric elements are        electrically connected in parallel.

EXAMPLE 19

A surgical instrument for coagulating and dissecting tissue, thesurgical instrument comprising:

a transducer assembly comprising:

-   -   a housing;    -   an ultrasonic transducer comprising:        -   a plurality of piezoelectric elements and a plurality of            electrodes arranged in a stack configuration having a first            end and a second end, wherein a first electrode is located            between a first pair of piezoelectric elements, a second            electrode is located between a second pair of piezoelectric            elements, a third electrode is located at the first end of            the stack configuration, and a fourth electrode is located            at the second end of the stack configuration;        -   a first spacer element in contact with the third electrode;        -   a second spacer element in contact with the fourth            electrode;    -   an end mass having a first end, a second end, and an aperture        therethrough, the end mass being positioned adjacent a first end        of the ultrasonic transducer, wherein the end mass is configured        to engage with the housing;    -   wherein the end mass is configured to compress the ultrasonic        transducer against an interior surface of the housing when the        end mass is engaged with the housing; and    -   wherein the first end of the end mass contacts the first spacer        element when the end mass compresses the ultrasonic transducer;        and    -   wherein the second spacer element contacts the interior surface        of the housing when the end mass compresses the ultrasonic        transducer.

EXAMPLE 20

A surgical instrument for coagulating and dissecting tissue, thesurgical instrument comprising:

a transducer assembly comprising:

-   -   a housing;    -   an ultrasonic transducer comprising:        -   a plurality of piezoelectric elements and a plurality of            electrodes arranged in a stack configuration having a first            end and a second end, wherein a first electrode is located            between a first pair of piezoelectric elements, a second            electrode is located between a second pair of piezoelectric            elements, a third electrode is located at the first end of            the stack configuration, and a fourth electrode is located            at the second end of the stack configuration;        -   a first spacer element in contact with the third electrode;        -   a second spacer element in contact with the fourth            electrode;    -   an end mass having a first end, a second end, and an aperture        therethrough, the end mass being positioned adjacent a first end        of the ultrasonic transducer, wherein the end mass is configured        to engage with the housing;    -   wherein the end mass is configured to compress the ultrasonic        transducer against an interior surface of the housing when the        end mass is engaged with the housing; and    -   wherein the first end of the end mass contacts the first spacer        element when the end mass compresses the ultrasonic transducer;        and    -   wherein the second spacer element contacts the interior surface        of the housing when the end mass compresses the ultrasonic        transducer.

EXAMPLE 21

The surgical instrument of Example 20, wherein the plurality ofpiezoelectric elements have a longitudinal axis and the end mass has alongitudinal axis that is aligned with the longitudinal axis of theplurality of piezoelectric elements.

EXAMPLE 22

The surgical instrument of Example 20 or 21, wherein the end masscomprises a distal portion having an opening defined therein, whereinthe ultrasonic transducer is configured to fit within the distal portionof the end mass and the housing is configured to engage with the endmass via a threaded connection between the housing and the distalportion of the end mass.

EXAMPLE 23

The surgical instrument of any one or more of Example 20 through 22,wherein the end mass comprises a wall that at least partially surroundsand houses the ultrasonic transducer.

EXAMPLE 24

The surgical instrument of any one or more of Example 20 through 23,wherein the electrode is a first electrode and wherein the ultrasonictransducer further comprises: a second electrode located at the firstend of the ultrasonic transducer and in contact with one surface of afirst piezoelectric element of the plurality of piezoelectric elements;and a third electrode located at a second end of the ultrasonictransducer and in contact with one surface of a second piezoelectricelement of the plurality of piezoelectric elements.

EXAMPLE 25

The surgical instrument of any one or more of Example 20 through 24,wherein the end mass comprises a torqueing feature that allows torque tobe applied to the end mass.

EXAMPLE 26

The surgical instrument of any one or more of Example 20 through 25,wherein the end mass is configured to engage with the housing via athreaded connection.

EXAMPLE 27

The surgical instrument of any one or more of Example 20 through 26,further comprising a conductive element adjacent the conduit section ofthe housing.

EXAMPLE 28

The surgical instrument of Example 27, wherein the conductive element atleast partially surrounds the conduit section of the housing and iselectrically isolated from the conduit section.

EXAMPLE 29

The surgical instrument of Example 27, further comprising an insulatorbetween the conductive element and the conduit section.

EXAMPLE 30

The surgical instrument of Example 27, wherein the electrode iselectrically coupled to the conductive element.

EXAMPLE 31

The surgical instrument of Example 27, wherein the electrode iselectrically coupled to the conductive element via at least one tab ofthe electrode.

EXAMPLE 32

The surgical instrument of any one or more of Example 20 through 31,wherein the end mass is bonded to the housing to create a seal around aninterior compartment defined when the housing and the end mass areengaged.

EXAMPLE 33

The surgical instrument of any one or more of Example 20 through 32,further comprising a surgical instrument housing, wherein the transducerassembly is located with the surgical instrument housing.

EXAMPLE 34

The surgical instrument of any one or more of Example 20 through 33,wherein, when the end mass compresses the ultrasonic transducer againstthe interior surface of the housing, the first end of the ultrasonictransducer contacts an interior surface of the end mass and a second endof the ultrasonic transducer is compressed against the interior surfaceof the housing.

EXAMPLE 35

The surgical instrument of any one or more of Example 20 through 34,wherein the electrode comprises an outer edge and an aperture thatdefines an inner edge of the electrode.

EXAMPLE 36

The surgical instrument of Example 35, wherein the inner edge comprisesat least one tab extending towards a center of the aperture.

EXAMPLE 37

The surgical instrument of Example 35, wherein the outer edge comprisesat least one tab extending outwards from a center of the aperture.

EXAMPLE 38

A surgical instrument for coagulating and dissecting tissue, thesurgical instrument comprising:

a transducer assembly comprising:

-   -   a housing comprising a conduit section and a base portion,        wherein a fluid passageway is defined through the conduit        section and the base portion;    -   an ultrasonic transducer comprising a plurality of piezoelectric        elements and a plurality of electrodes arranged in a stack        configuration, the ultrasonic transducer having a longitudinal        axis, a first end, and a second end, wherein a first borehole is        defined through the ultrasonic transducer, wherein a first        electrode is located between each pair of piezoelectric        elements, a second electrode is located at the first end of the        ultrasonic transducer, and a third electrode is located at the        second end of the ultrasonic transducer;    -   an end mass comprising a second borehole defined therethrough,        the end mass positioned along the longitudinal axis and adjacent        a first end of the ultrasonic transducer, wherein the end mass        is configured to engage with the housing; and    -   wherein the conduit section of the housing is configured to pass        through the first borehole of the ultrasonic transducer and the        second borehole of the end mass; and    -   wherein the end mass is configured to compress the ultrasonic        transducer against a surface of the housing when the end mass is        engaged with the housing; and    -   wherein a first piezoelectric element of the plurality of        piezoelectric elements and a second piezoelectric element of the        plurality of piezoelectric elements are electrically connected        in parallel.

EXAMPLE 39

A transducer assembly comprising:

a housing comprising a conduit section and a base portion, wherein afluid passageway is defined through the conduit section and the baseportion;

a conductive element at least partially surrounding the conduit sectionof the housing; and

a insulator positioned between the conductive element and the conduitsection, wherein the insulator electrically isolates the conductiveelement from the conduit section;

an ultrasonic transducer comprising a plurality of piezoelectricelements and a plurality of electrodes arranged in a stackconfiguration, the ultrasonic transducer having a longitudinal axis, afirst end, and a second end, wherein a first borehole is defined throughthe ultrasonic transducer, wherein a first electrode is located betweeneach pair of piezoelectric elements, a second electrode is located atthe first end of the ultrasonic transducer, and a third electrode islocated at the second end of the ultrasonic transducer, wherein thefirst electrode is electrically coupled to the conductive element; and

an end mass comprising a second borehole defined therethrough, the endmass positioned along the longitudinal axis and adjacent a first end ofthe ultrasonic transducer, wherein the end mass is configured to engagewith the housing; and

wherein the conduit section of the housing is configured to pass throughthe first borehole of the ultrasonic transducer and the second boreholeof the end mass; and

wherein the end mass is configured to compress the ultrasonic transduceragainst a surface of the housing when the end mass is engaged with thehousing; and

wherein a first piezoelectric element of the plurality of piezoelectricelements and a second piezoelectric element of the plurality ofpiezoelectric elements are electrically connected in parallel.

1-12. (canceled)
 13. A surgical instrument for coagulating anddissecting tissue, the surgical instrument comprising: a transducerassembly comprising: a housing comprising a conduit section and a baseportion, wherein the conduit section and the base portion define a fluidpassageway; an ultrasonic transducer comprising a plurality ofpiezoelectric elements and a plurality of electrodes arranged in a stackconfiguration, wherein at least one of the plurality of electrodes islocated between at least one pair of the plurality of piezoelectricelements, and wherein a first borehole is defined through the ultrasonictransducer; and an end mass comprising a second borehole definedtherethrough, wherein a surface of the end mass is positioned adjacent afirst end of the ultrasonic transducer, wherein the end mass isconfigured to engage with the housing; and wherein: the conduit sectionof the housing is configured to pass through the first borehole of theultrasonic transducer and the second borehole of the end mass; and theend mass is configured to compress the ultrasonic transducer against aninterior surface of the housing when the end mass is engaged with thehousing.
 14. The surgical instrument of claim 13, wherein the end masscomprises a wall that at least partially surrounds and houses theultrasonic transducer.
 15. The surgical instrument of claim 13, whereinthe stack configuration comprises: a first electrode of the plurality ofelectrodes located at a first end of the ultrasonic transducer, whereinthe first electrode is in contact with a surface of a firstpiezoelectric element of the plurality of piezoelectric elements; and asecond electrode of the plurality of electrodes located at a second endof the ultrasonic transducer, wherein the second electrode is in contactwith a surface of a second piezoelectric element of the plurality ofpiezoelectric elements.
 16. The surgical instrument of claim 13, whereinthe end mass comprises a torqueing feature that allows torque to beapplied to the end mass.
 17. The surgical instrument of claim 13,further comprising: a conductive element positioned adjacent the conduitsection of the housing, wherein the conductive element at leastpartially surrounds the conduit section of the housing; and an insulatorpositioned between the conductive element and the conduit section,wherein the insulator is configured to electrically isolate theconductive element from the conduit section.
 18. The surgical instrumentof claim 17, wherein each of the plurality of electrodes is electricallycoupled to the conductive element via at least one tab of eachelectrode.
 19. The surgical instrument of claim 13, wherein the end massis bonded to the housing to create a seal around an interior compartmentdefined when the housing and the end mass are engaged.
 20. The surgicalinstrument of claim 13, wherein the end mass is configured to compressthe ultrasonic transducer against an interior surface of the housingwhen the end mass is engaged with the housing comprises the first end ofthe ultrasonic transducer in contact with an interior surface of the endmass and a second end of the ultrasonic transducer compressed againstthe interior surface of the housing.
 21. The surgical instrument ofclaim 13, wherein each of the plurality of electrodes comprises an outeredge and an aperture that defines an inner edge of each electrode. 22.The surgical instrument of claim 21, wherein: the inner edge comprisesat least one tab extending towards a center of the aperture; and theouter edge comprises at least one tab extending outwards from the centerof the aperture.
 23. The surgical instrument of claim 13, wherein: theend mass is configured to engage with the housing via a threadedconnection; a first piezoelectric element of the plurality ofpiezoelectric elements; and a second piezoelectric element of theplurality of piezoelectric elements are electrically connected inparallel. 24-27. (canceled)